Primary Arms | SLx MD-21 Microdot | 21mm | 2 MOA

The Primary Arms SLx MD-21 is a compact micro red dot sight designed for fast target acquisition in close-quarters and low-light environments. It is lightweight and constructed to provide a rigid mounting interface for Picatinny-equipped platforms. Night-vision compatibility and power-saving Autolive technology make it suitable for long-duration use in varied conditions.

Product Specifications

• The product type is Red Dot.
• The model is listed as Microdot (SLx MD-21).
• The reticle is a Red Dot.
• The dot size is 2 MOA.
• The optical power is 1X.
• The objective measures 21mm.
• The finish color is Black with an anodized coating.
• The unit is designed to fit Picatinny rails.
• The sight is specified as Night Vision Compatible.
• The sight incorporates Autolive technology to shut off the reticle after inactivity and restore it on motion.
• The LED emitter is described as an upgraded unit for true red dot brightness and extended runtime.
• The mounting hardware is described as upgraded to provide rigidity and consistent alignment.
• The listed weight in the product description is 5 ounces.
• The sight is intended for close-quarters and low-light applications such as training or competition.
• The UPC is 818500018254.

Compact and purposeful, the SLx MD-21 provides a low-profile aiming solution for close-quarters work and dynamic range drills. Its combination of a small 2 MOA dot, night-vision compatibility, and motion-activated power saving makes it a practical optic for shooters who prioritize lightweight equipment and consistent, repeatable mounting. The upgraded hardware and emitter support reliable on‑gun performance across extended use.

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