The Primary Arms SLx MD-21S (model 810028) is an advanced micro dot sight that incorporates the latest technologies and materials to deliver exceptional CQB performance. Weighing only 5 ounces, it is both lightweight and rugged, featuring upgraded mounting hardware for guaranteed rigidity and precision.

Key Specifications

• Manufacturer: Primary Arms
• Model: SLx (MD-21S)
• Product Type: Red dot sight
• Magnification: 1x
• Reticle: ACSS CQB
• Illumination Control: AutoLive motion-sensing
• Weight: 5 oz.
• Reticle Color: Red
• Mounting Hardware: Upgraded for rigidity and precision

Frequently Asked Questions

What does the ACSS CQB reticle add over a plain dot? The ACSS CQB reticle is built around close-quarters ranging and holdover references, giving faster follow-up shot references than a simple red dot in fast, close-range engagements.

Is the MD-21S the same physical size as the standard MD-21? Yes, it uses the same lightweight 5 oz. micro dot body; the difference is the ACSS CQB reticle instead of a plain 2 MOA dot.

Buy the Primary Arms SLx MD-21S ACSS CQB Red Dot Sight

Shop the Primary Arms lineup or browse more of our Red Dot Sights selection at Schaefer Defense.