The Primary Arms GLx MD-21S ACSS-CQB pairs the duty-grade solar red dot sight with the ACSS-CQB reticle — a fine centre aiming point inside a large outer ring that your eye picks up instantly at close-quarters speed.
Solar Failsafe backs up the CR2032, AutoLive wakes the sight on movement, and side push-buttons cycle night-vision-compatible brightness in a shockproof, waterproof aluminium housing. Low and absolute co-witness mounts included.
How It Compares
Want a plain dot? The MD-21S 2 MOA. What is ACSS? Read our ACSS guide. Browse rifle dot sights and all red dots.
Key Features
- ACSS-CQB reticle — centre dot + fast outer ring
- Solar Failsafe + AutoLive motion sensing
- Side push-button brightness, NV compatible
- Low + absolute co-witness mounts included
- Waterproof, shockproof aluminium; lifetime warranty
Technical Specifications
| Reticle |
ACSS-CQB (red) |
| Power |
CR2032 + Solar Failsafe; AutoLive |
| Size |
21mm micro |
| Mounts |
Low + absolute co-witness (included) |
| SKU / MPN / UPC |
PA-GLX-MD-21S-ACSS / 810026 / 818500018285 |
What's Included
- GLx MD-21S ACSS sight, low mount, co-witness riser + spacer, CR2032, tools, manual
UK Delivery & Support
UK-stocked and dispatched tracked from our UK warehouse — no import duties or customs delays — backed by UK-based support and Primary Arms' lifetime warranty.
Frequently Asked Questions
Why choose the ACSS-CQB over a plain dot?
The outer ring draws your eye to centre faster under stress, while the fine centre point keeps precision — a genuine best-of-both for CQB work.
Is it night-vision compatible?
Yes — dedicated NV brightness settings.
