The A-Spec M3 is manufactured to be compatible for uses with a Shield RMS-CA(R) footprint, and it boasts a red auto-brightness control reticle to accommodate shooting at any time, day or night. This optic is perfect for subcompact guns, and is notoriously durable - aluminum alloy housing, IP55 water-resistant, shockproof, able to withstand up to .375 H&H caliber and operate in temperatures from -22F to 122F. With a battery life up to 100,000 hours and an included rubber cover, low-profile fixed mount and manual, the A-Spec M3 is guaranteed to help you Make Your Mark. Included in Package: Rubber Cover Low Profile Fixed Mount CR2032 Battery Batteries Used: Type: CR2032 Quantity: 1 Features: Fits pistols with Shield RMS-CA(R) footprint Auto-brightness control reticle Cowitness with standard pistol sights Red reticle illumination Lightweight compact aluminum alloy housing Rugged aluminum alloy housing IP55 water-resistant Shockproof Battery life up to 100,000 hours