If you have a pistol or mounting plate with the DeltaPoint Pro footprint and want an enclosed red dot, you have likely considered these five options:
- Osight SE DPP
- Holosun SCS 320
- Vortex Venom Enclosed
- Vortex Defender-ST Enclosed Solar
- SIG Sauer ROMEO-X Enclosed Pro
Although all five optics use the DPP footprint and feature an enclosed-emitter design, each one serves a different purpose. Some prioritize affordability, while others focus on window size, solar power, low deck height, or premium construction.
In this article, we will compare the key features of each optic and explain which type of shooter may benefit most from choosing it.
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Starts at $203.99 
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Starts at $399.99 
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Starts at $199.99 
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Starts at $379.99 
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Starts at $529.99 
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Quick Comparison
| Optic | Window Size | Deck Height | Reticle Options | Power System | Housing | Price |
|---|---|---|---|---|---|---|
| Osight SE DPP | 0.91 × 0.71 in. | 7.5 mm | Red 2 MOA dot, 32 MOA circle, or circle-dot | Side-loading CR1620 | 7075-T6 aluminum | $240 |
| Holosun SCS 320 | 0.90 × 0.63 in. | 8 mm | Green 2 MOA dot, 32 MOA circle, or circle-dot | Solar with internal rechargeable battery | 7075-T6 aluminum | $400 |
| Vortex Venom Enclosed | 0.87 × 0.78 in. | 10 mm | Red 3 or 6 MOA dot | Side-loading CR2032 | 6061 aluminum | $200 |
| Vortex Defender-ST Enclosed Solar | 0.91 × 0.79 in. | 7.65 mm | Red 3 MOA dot, 32 MOA circle, or circle-dot | Solar-assisted CR2032 | 7075 aluminum | $380 |
| SIG ROMEO-X Enclosed Pro | 0.81 × 0.62 in. | 5.9 mm | Red or green circle-dot, 3 MOA dot, or 6 MOA dot | Side-loading CR1632 | 7075 aluminum | $530–$590 |
Prices shown are the prices used for this comparison and may vary by model, reticle, color, or retailer.
What Do These Five Optics Have in Common?
All five are enclosed-emitter pistol optics designed around the DeltaPoint Pro footprint.
In an open-emitter optic, the LED emitter is exposed behind the front lens. If enough water, mud, lint, or debris gets between the emitter and the lens, it can interfere with the projected dot.
An enclosed optic seals the emitter between a front and rear lens. This gives the optic additional protection from environmental conditions and everyday debris.
That can be valuable on a concealed-carry, duty, home-defense, or general-use pistol. However, each of these optics approaches the enclosed DPP category differently.
The Venom focuses on affordability. The Osight combines a low deck and multi-reticle system at a value-oriented price. The SCS 320 is designed for automatic, low-maintenance operation. The Defender-ST combines solar power with traditional controls. The ROMEO-X Enclosed Pro focuses on an extremely low deck height and premium construction.
Window Size Comparison
Window size determines how much open viewing space surrounds the reticle.
A larger window does not automatically make an optic more accurate, but it can provide more visual forgiveness when presenting the pistol, shooting from an awkward position, transitioning between targets, or tracking the dot through recoil.
| Optic | Window Length | Window Height |
|---|---|---|
| Vortex Defender-ST Enclosed | 0.91 in. | 0.79 in. |
| Vortex Venom Enclosed | 0.87 in. | 0.78 in. |
| Osight SE DPP | 0.91 in. | 0.71 in. |
| Holosun SCS 320 | 0.90 in. | 0.63 in. |
| SIG ROMEO-X Enclosed Pro | 0.81 in. | 0.62 in. |
Vortex Defender-ST Enclosed
The Defender-ST has the largest overall window in this comparison.
Its window measures 0.91 inches long and 0.79 inches tall. It ties the Osight for the greatest window length while offering the most window height.
For those who prioritize the largest possible viewing area, the Defender-ST has the clear advantage.
Vortex Venom Enclosed
The Venom has a 0.87 × 0.78-inch window.
It is slightly narrower than the Defender-ST and Osight, but it is nearly as tall as the Defender-ST. This gives it a tall, relatively square viewing area.
The Venom offers one of the largest windows in the group despite being the least expensive optic. However, its tall window is paired with the highest deck height, which causes the entire viewing area to sit higher above the slide.
Osight SE DPP
The Osight has a 0.91 × 0.71-inch window.
It ties the Defender-ST for the longest window in the comparison. It is not as tall as either Vortex optic, but it provides a wide sight picture while maintaining a relatively low deck height.
Holosun SCS 320
The SCS 320 has a 0.90 × 0.63-inch window.
Its window is nearly as long as the Osight and Defender-ST, but it provides less vertical viewing space. It has the second-shortest window in the group.
SIG ROMEO-X Enclosed Pro
The ROMEO-X Enclosed Pro has a 0.81 × 0.62-inch window, making it the smallest window in this comparison.
The SIG gives up some viewing area in exchange for its extremely low deck height and compact overall design. Someone who prioritizes the largest possible window may prefer one of the Vortex options or the Osight, while someone prioritizing a low-profile installation may prefer the SIG.
Deck Height Comparison
Deck height is the distance between the optic’s mounting surface and the bottom of its viewing window.
A lower deck places the window closer to the slide. This may allow standard-height or shorter iron sights to remain visible through the optic, depending on the pistol and sight configuration.
| Optic | Deck Height |
|---|---|
| SIG ROMEO-X Enclosed Pro | 5.9 mm |
| Osight SE DPP | 7.5 mm |
| Vortex Defender-ST Enclosed | 7.65 mm |
| Holosun SCS 320 | 8 mm |
| Vortex Venom Enclosed | 10 mm |
SIG ROMEO-X Enclosed Pro: Lowest Deck
The ROMEO-X Enclosed Pro has the lowest deck height by a significant margin.
At 5.9 mm, its deck is:
- 1.6 mm lower than the Osight
- 1.75 mm lower than the Defender-ST
- 2.1 mm lower than the SCS 320
- 4.1 mm lower than the Venom
SIG designed the ROMEO-X Enclosed Pro to allow co-witnessing with standard-height iron sights on compatible pistols.
This is one of the optic’s biggest advantages. A buyer who wants the lowest possible optic position may find the SIG worth its higher price.
Osight SE DPP
The Osight has the second-lowest deck height at 7.5 mm.
It provides a lower viewing-window position than the Holosun and Venom while sitting only 0.15 mm lower than the Defender-ST.
Vortex Defender-ST Enclosed
The Defender-ST has a 7.65 mm deck height.
It combines the largest viewing window with one of the lowest deck measurements. This gives it a large sight picture without causing the bottom of the window to sit unusually high above the slide.
Holosun SCS 320
The SCS 320 has an 8 mm deck height.
It sits slightly higher than the Osight and Defender-ST, but the difference is relatively small.
Vortex Venom Enclosed
The Venom has a 10 mm deck height, making it the tallest optic deck in this comparison.
Its deck is 4.1 mm taller than the ROMEO-X Enclosed Pro and 2.5 mm taller than the Osight.
The Venom’s large vertical window helps provide a generous sight picture, but the entire window begins higher above the slide. That is an important tradeoff for anyone prioritizing a low mount or iron-sight visibility.
Reticle Comparison
The five optics offer several different reticle configurations.
| Optic | Reticle Color | Reticle Options |
|---|---|---|
| Osight SE DPP | Red | Selectable 2 MOA dot, 32 MOA circle, or circle-dot |
| Holosun SCS 320 | Green | Selectable 2 MOA dot, 32 MOA circle, or circle-dot |
| Vortex Venom Enclosed | Red | Fixed 3 or 6 MOA dot |
| Vortex Defender-ST Enclosed | Red | Selectable 3 MOA dot, 32 MOA circle, or circle-dot |
| SIG ROMEO-X Enclosed Pro | Red or green | Available in circle-dot, 3 MOA, or 6 MOA versions |
An important distinction is that the Osight, Holosun, and Defender-ST allow the shooter to switch between multiple reticle configurations on the same optic.
The Venom and ROMEO-X Enclosed Pro are available in different reticle versions. Buyers select their preferred reticle when purchasing the optic.
Osight SE DPP Reticle
The Osight uses a red Multi-Reticle System with three selectable configurations:
- 2 MOA dot
- 32 MOA circle
- 2 MOA dot with 32 MOA circle
The small center dot provides a precise aiming point, while the larger circle can be easier to find quickly during the presentation.
Holosun SCS 320 Reticle
The SCS 320 uses a green Multi-Reticle System.
It provides:
- 2 MOA dot
- 32 MOA circle
- 2 MOA dot with 32 MOA circle
The SCS 320 is the only optic in this comparison that combines a switchable multi-reticle system with green illumination only.
Vortex Venom Enclosed Reticle
The Venom is available with either a 3 MOA or 6 MOA red dot.
Each version uses one fixed dot size. The shooter cannot switch between the 3 and 6 MOA reticles after purchasing the optic.
The 3 MOA version provides a finer aiming point. The 6 MOA version provides a larger dot that may be easier to locate quickly.
Vortex Defender-ST Enclosed Reticle
The Defender-ST uses a red multi-reticle system with:
- 3 MOA dot
- 32 MOA circle
- 3 MOA dot with 32 MOA circle
It provides the same general reticle configurations as the Osight and Holosun but uses a slightly larger 3 MOA center dot.
SIG ROMEO-X Enclosed Pro Reticle
The ROMEO-X Enclosed Pro is available in:
- Circle-dot
- 3 MOA dot
- 6 MOA dot
It is also available with either red or green illumination.
This gives the SIG the widest selection of color and fixed-reticle combinations. However, these are separate optic configurations rather than a switchable multi-reticle system.
You will need to select your desired reticle and color when purchasing the optic.
Battery and Power Comparison
The five optics use four different approaches to power management.
| Optic | Battery | Listed Runtime | Solar |
|---|---|---|---|
| Osight SE DPP | Side-loading CR1620 | Up to 75,000 hours | No |
| Holosun SCS 320 | Internal rechargeable battery | 20,000-hour reserve | Yes |
| Vortex Venom Enclosed | Side-loading CR2032 | 20,000 hours | No |
| Vortex Defender-ST Enclosed | Side-loading CR2032 | 35,000 to 150,000 hours | Yes |
| SIG ROMEO-X Enclosed Pro | Side-loading CR1632 | 20,000 hours | No |
Holosun SCS 320: Set It and Forget It
The SCS 320 has the most unique power system in the comparison.
Instead of using a removable coin-cell battery, it uses an internal rechargeable battery that is replenished through Holosun’s Solar Charging Sight technology.
The internal battery provides a 20,000-hour reserve. With regular exposure to light, the optic is designed to continue operating without routine battery replacement.
The SCS 320 also relies on automatic brightness control. Light sensors monitor the environment and adjust the reticle automatically.
The optic has one button that allows the user to:
- Turn the optic on or off
- Cycle through the reticle choices
- Activate the high-brightness override
The brightness override holds the reticle at maximum brightness for 30 minutes before returning to automatic operation.
This is the most hands-off optic in the comparison. Once the preferred reticle is selected, the shooter can allow the optic to manage brightness and charging automatically.
That makes the SCS 320 attractive to someone who wants a true set-it-and-forget-it optic. However, someone who prefers full manual brightness control may be better served by one of the other options.
Vortex Defender-ST Enclosed: Solar With a Replaceable Battery
The Defender-ST combines solar assistance with a removable CR2032 battery.
Vortex lists the battery life at:
- 35,000 hours without solar assistance
- Up to 150,000 hours with solar assistance
Its Auto D-TEC technology detects lighting conditions and determines whether the optic should draw power from the solar panel or battery.
Unlike the SCS 320, the Defender-ST retains the operation of a more traditional red dot. It has side-mounted controls and 12 brightness settings:
- 10 daylight settings
- 2 night-vision settings
It also includes button lockout, motion activation, and a 10-minute automatic shutoff.
The side-loading battery can be replaced without removing the optic or disturbing zero.
Osight SE DPP: Long Battery Life and Manual Control
The Osight uses a side-loading CR1620 battery.
Its listed runtime depends on the selected reticle:
| Reticle Setting | Listed Runtime |
|---|---|
| 2 MOA dot | 75,000 hours |
| 32 MOA circle | 50,000 hours |
| Circle-dot | 46,600 hours |
The Osight provides ten brightness settings:
- 8 daylight settings
- 2 night-vision settings
It also includes motion activation, memory, and a low-battery indicator.
The optic powers down after three minutes without movement and reactivates when motion is detected.
This gives the Osight a more traditional user-controlled system than the SCS 320. The shooter selects the brightness level and reticle, while the motion sensor helps conserve battery life.
Vortex Venom Enclosed: Simple CR2032 Power
The Venom uses a side-loading CR2032 battery with a listed runtime of 20,000 hours.
It has ten brightness settings:
- 8 daylight settings
- 2 night-vision settings
Motion activation turns the optic on when movement is detected, while a 10-minute automatic shutoff helps conserve battery life.
The brightness buttons are positioned on top of the optic. Some shooters may find the top-mounted controls easy to access, while others may prefer the more traditional side-control arrangement used on the Defender-ST.
The Venom also has a noticeable battery compartment on the side of its housing. It allows the battery to be changed without removing the optic, but some users may find its appearance distracting.
SIG ROMEO-X Enclosed Pro: Traditional Battery With MOTAC
The ROMEO-X Enclosed Pro uses a side-loading CR1632 battery with a listed runtime of 20,000 hours.
SIG’s MOTAC motion-activated illumination system powers the optic according to movement, helping preserve battery life when the pistol is not in use.
The optic offers 15 illumination settings:
- 12 daylight settings
- 3 night-vision settings
It has more total brightness settings than the other optics in this comparison.
The side-loading battery can be replaced without removing the optic or requiring the shooter to re-zero it.
Unlike the Holosun and Defender-ST, the SIG does not use solar power. Its power system is closer to a traditional premium pistol optic with manual illumination settings and motion activation.
Housing Material and Construction
Four of the five optics use 7075-series aluminum.
| Optic | Housing Material |
|---|---|
| Osight SE DPP | 7075-T6 aluminum |
| Holosun SCS 320 | 7075-T6 aluminum |
| Vortex Defender-ST Enclosed | 7075 aluminum |
| SIG ROMEO-X Enclosed Pro | 7075 aluminum |
| Vortex Venom Enclosed | 6061 aluminum |
7075 Aluminum Options
The Osight, SCS 320, Defender-ST, and ROMEO-X Enclosed Pro all use 7075-series aluminum housings.
This material is commonly associated with more premium pistol-optic construction.
The SCS 320 is rated IPX8 for water resistance, while the Osight and ROMEO-X Enclosed Pro are rated IPX7.
The Defender-ST also includes Vortex’s Fast-Rack textured front surface. This provides an aggressive contact area that can be used to manipulate the pistol slide against a hard surface.
Vortex Venom’s 6061 Aluminum Housing
The Venom uses 6061 aluminum instead of 7075.
This is one of the differences that helps separate the Venom from the more expensive Defender-ST within the Vortex lineup.
Its housing still provides an enclosed optical system designed to protect against moisture and debris, but its construction is positioned as the more budget-oriented option in this comparison.
SIG ROMEO-X Enclosed Pro Construction
The ROMEO-X Enclosed Pro uses a fully enclosed CNC-machined 7075 aluminum housing.
It also includes:
- An aspherical glass lens
- A patent-pending beryllium copper flexure arm
- IPX7 water resistance
- Black or FDE housing options
- Assembly in the United States
Its construction, ultra-low deck, and additional configuration choices help explain why it is the most expensive optic in the comparison.
Price Comparison
Price creates three fairly clear levels within this group.
| Optic | Price |
|---|---|
| Vortex Venom Enclosed | $200 |
| Osight SE DPP | $240 |
| Vortex Defender-ST Enclosed Solar | $380 |
| Holosun SCS 320 | $400 |
| SIG ROMEO-X Enclosed Pro | $530–$590 |
Vortex Venom Enclosed: $200
The Venom is the least expensive optic in the comparison.
It provides:
- Enclosed-emitter protection
- A large and tall viewing window
- Manual brightness control
- Motion activation
- Side-loading battery
- 3 or 6 MOA dot options
The tradeoffs are its 6061 housing, fixed dot reticle, 20,000-hour runtime, noticeable battery compartment, and 10 mm deck height.
Osight SE DPP: $240
The Osight costs only $40 more than the Venom.
For that additional cost, it provides:
- 7075-T6 construction
- A selectable multi-reticle system
- Lower 7.5 mm deck
- Wider viewing window
- Longer listed battery life
- Manual brightness settings
- Motion activation
Based on the listed specifications, the Osight offers a strong amount of functionality for its price.
Vortex Defender-ST Enclosed Solar: $380
The Defender-ST costs $140 more than the Osight and $180 more than the Venom.
Its advantages include:
- Largest window in the comparison
- Low 7.65 mm deck
- Red multi-reticle system
- Solar-assisted battery life
- Traditional side controls
- Replaceable CR2032 battery
- 7075 aluminum housing
- Button lockout
- Fast-Rack front texturing
It is the most feature-rich option for someone who wants solar assistance without giving up the normal controls and replaceable battery of a traditional red dot.
Holosun SCS 320: $400
The SCS 320 is only $20 more than the Defender-ST.
Its value comes from its unique operation rather than from having the largest window or the greatest number of manual controls.
The SCS 320 offers:
- Solar charging
- Internal rechargeable battery
- Automatic brightness
- Green multi-reticle system
- Minimal user interaction
- 7075-T6 construction
- IPX8 water resistance
It is designed for the shooter who wants to install the optic, select a reticle, and rarely interact with it afterward.
SIG ROMEO-X Enclosed Pro: $530 to $590
The ROMEO-X Enclosed Pro is by far the most expensive optic in the comparison.
Depending on the reticle, illumination color, and housing color, pricing ranges from approximately $530 to $590.
Its premium price reflects features such as:
- Extremely low 5.9 mm deck
- Standard-height iron-sight co-witness capability on compatible pistols
- 7075 aluminum construction
- Red or green illumination
- Multiple fixed-reticle options
- Black or FDE housing
- 15 illumination settings
- U.S. assembly
The SIG does not have the largest window, solar charging, or the longest battery life. Its primary advantages are its low mounting height, premium construction, configuration choices, and iron-sight compatibility.
Who Is the Osight SE DPP For?
The Osight SE DPP is a strong option for someone who wants premium-style features without moving into the $380 to $590 price range.
It provides:
- Red multi-reticle system
- 7075-T6 aluminum construction
- Side-loading battery
- Manual brightness control
- Long listed runtime
- Second-lowest deck height
- Wide 0.91-inch window
- $240 price
The Osight is likely the best fit for someone who wants a low-mounted, manually adjustable, multi-reticle optic while getting as much functionality as possible for the money.
Who Is the Holosun SCS 320 For?
The Holosun SCS 320 is for the shooter who wants a true set-it-and-forget-it optic.
It has no removable battery to replace and no traditional brightness menu to manage. Its solar system charges the internal battery, while the optic automatically selects the reticle brightness.
It is also the only optic in this comparison that combines green illumination with a switchable multi-reticle system.
The SCS 320 is likely the best fit for someone who wants:
- Green illumination
- Automatic brightness
- No routine battery replacement
- Solar charging
- Minimal controls
- A low-maintenance defensive or duty optic
Someone who wants to manually control brightness at all times may prefer the Osight, Venom, Defender-ST, or ROMEO-X.
Who Is the Vortex Venom Enclosed For?
The Vortex Venom Enclosed is for the buyer who wants an enclosed DPP optic at the lowest possible price.
It offers:
- $200 price
- Large and tall viewing window
- Simple 3 or 6 MOA red dot
- Manual brightness adjustment
- Motion activation
- Side-loading CR2032 battery
The primary tradeoffs are its 6061 housing, tallest deck height, fixed reticle, and shorter listed battery life.
The Venom is likely the best fit for someone who wants a straightforward enclosed optic and is more concerned with affordability than solar power, a low deck, or multiple selectable reticles.
Who Is the Vortex Defender-ST Enclosed Solar For?
The Defender-ST is for someone who wants a premium enclosed optic while retaining the normal operation of a traditional red dot.
It provides:
- Largest window in the group
- Low deck height
- Red multi-reticle system
- Solar-assisted battery life
- Replaceable CR2032 battery
- Manual brightness control
- Side-mounted buttons
- Button lockout
- 7075 aluminum construction
The Defender-ST combines many of the strongest features from the other optics.
It is likely the best fit for someone who wants the largest window, solar assistance, manual controls, and a replaceable battery in one optic.
Who Is the SIG ROMEO-X Enclosed Pro For?
The ROMEO-X Enclosed Pro is for the shooter who prioritizes the lowest possible deck height and largest choice of reticles.
Its 5.9 mm deck is significantly lower than every other optic in the comparison. It is designed to provide co-witnessing with standard-height iron sights on compatible pistols.
It also offers more configuration choices than the other optics, including:
- Red or green illumination
- 3 MOA dot
- 6 MOA dot
- Circle-dot
- Black or FDE housing
The SIG is likely the best fit for someone who wants:
- The lowest optic deck
- Standard-height iron-sight compatibility
- Premium 7075 construction
- Traditional battery operation
- Multiple color and reticle choices
- A black or FDE housing
- A U.S.-assembled optic
Its biggest disadvantage is price. At approximately $530 to $590, it costs considerably more than every other optic in the comparison.
|
Starts at $203.99
|
Starts at $399.99
|
Starts at $199.99
|
|
Starts at $379.99
|
Starts at $529.99
|
Final Thoughts: Which Enclosed DPP Optic Should You Choose?
All five optics provide an enclosed-emitter design and DPP-footprint compatibility, but each one has a different strength.
The Vortex Venom Enclosed is the budget option. It provides a large window and straightforward dot reticle for $200, but it has the tallest deck and uses a 6061 aluminum housing.
The Osight SE DPP offers the strongest combination of specifications and price. It provides a wide window, low deck, 7075-T6 construction, switchable multi-reticle system, and long battery life for $240.
The Vortex Defender-ST Enclosed Solar is the premium feature-focused option. It has the largest window, low deck, solar-assisted battery life, manual controls, a replaceable battery, and a selectable red multi-reticle system.
The Holosun SCS 320 is the set-it-and-forget-it option. Its solar charging, internal battery, automatic brightness, and green multi-reticle system make it ideal for someone who wants minimal maintenance.
The SIG ROMEO-X Enclosed Pro is the ultra-low premium option. It has the lowest deck by a wide margin, offers standard-height iron-sight co-witness potential, and is available in several reticle, color, and housing configurations. However, it is also the most expensive.
| Your Priority | Best Fit |
|---|---|
| Lowest price | Vortex Venom Enclosed |
| Best overall value | Osight SE DPP |
| Largest window and premium manual controls | Vortex Defender-ST Enclosed Solar |
| Automatic, low-maintenance operation | Holosun SCS 320 |
| Lowest deck and standard iron-sight co-witness | SIG ROMEO-X Enclosed Pro |
