Primary Arms SLx MD-21 Push Button 21mm Microdot w/ AutoLive, 2 MOA Red Reticle - PA-SLX-MD-21

Primary Arms SLx MD-21 Micro Red Dot Sight – 2 MOA Dot

The SLx MD-21 is the next evolution in the trusted SLx line of optics—delivering unmatched performance in a compact, rugged package. Weighing in at just 5 ounces, the MD-21 is built for speed, precision, and reliability in close-quarters engagements. It features an upgraded LED emitter that produces a crisp Red Dot Bright™ 2 MOA reticle, fully compatible with night vision and optimized for daylight visibility with 12 brightness settings.

Designed for modern shooters, the MD-21 includes Autolive™ technology that conserves battery life by automatically powering down after two minutes of inactivity—and instantly powers back on when motion is detected. The robust aluminum housing is shockproof, waterproof, and hardcoat anodized for maximum durability in the harshest environments.

Whether you prefer an absolute co-witness or lower 1/3rd mount, the MD-21 comes ready with both. It’s also compatible with standard microdot mounts like Aimpoint Micro (T1/T2 footprint). Need a taller setup?

Key Features:

• Ultra-bright 2 MOA Red Dot Bright™ reticle

• Autolive™ motion-sensing technology for extended battery life

• Night vision compatible with upgraded LED emitter

• Top-mounted push-button brightness controls

• Fully multi-coated lens for optimal light transmission

• Includes both absolute and lower 1/3 co-witness mounts

• Lightweight 5 oz design with rugged aluminum construction

• Standard microdot footprint for broad mount compatibility

• Backed by Primary Arms' Lifetime Warranty

Specifications:

• Weight: 5 oz

• Battery: CR2032 (3V)

• Brightness Levels: 12

• Click Value: 1/2 MOA

• Finish: Hardcoat Anodized

• Mounting Interface: Picatinny, Aimpoint Micro Compatible

• Waterproof / Shockproof: Yes

• Warranty: Lifetime

Part of the SLx Series, trusted for innovation, reliability, and unbeatable value. Every SLx optic undergoes rigorous field-testing to ensure performance in real-world conditions.

Free Shipping: All orders ship free via UPS Ground/USPS/FedEx which takes 1-5 business days. We also offer UPS 2nd Day air for $9.99.

Same Day Shipping:* UPS only accepts ground shipments on Weekdays. Therefore any UPS Ground order we receive will ship same day if ordered before 2PM EST on Weekdays only.

Hassle Free Returns: We have a 30 day return policy. If you want to return your item for whatever reason just contact us and we'll send you a pre-paid label just like Amazon.