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 CoverLow Profile Fixed MountCR2032 BatteryBatteries Used:Type: CR2032Quantity: 1Features:Fits pistols with Shield RMS-CA(R) footprintAuto-brightness control reticleCowitness with standard pistol sightsRed reticle illuminationLightweight compact aluminum alloy housingRugged aluminum alloy housingIP55 water-resistantShockproofBattery life up to 100,000 hours