Primary Arms Classic Series 21mm Micro Reflex Sight with Autolive 3 MOA Red Dot Black. The Micro Reflex Sight is optimized for compact and micro compact pistols for concealed carry as it features a slightly smaller 21mm lens to keep the profile as slim as possible when mounting on smaller pistols eliminating any overhang on the slide. Even though the lens is smaller than the mini the square profile offers an unobstructed field of view allowing you to have a clear sight picture every time you present your pistol. It utilizes the RMSc footprint for a wide range of compatibility with milled slides and adapter plates and houses a bottom mounted CR2032 battery offering up to 40k hours of battery life on the medium setting. With 10 total illumination settings and a daylight bright 3 MOA red dot this reflex sight is sure to be quick to pick up and easy to use. The lens is fully multicoated for scratch and fog resistance and the 6061 Aluminum housing is extremely durable. If you are looking for a new red dot for concealed carry you can't go wrong with the Primary Arms MRSC. Specifications for Primary Arms Classic Series 21mm Micro Reflex Sight with Autolive 3 MOA Red Dot: Manufacturer: Primary Arms Color: Black Fabric/Material: 6061 Aluminum Magnification: 1 x Objective Lens Diameter: 21 mm Objective Window Size: 21 mm Reticle: 2 MOA Dot Illumination Type: LED Illumination Color: Red Brightness Settings: 10 Battery Type: CR2032 Battery Life: 40000 hours Weight: 0.56 oz Red Dot Sights-Footprint: RMSc Package Contents: Primary Arms Classic Series 21mm Micro Reflex Sight with Autolive 3 MOA Red Dot Primary Arms 810044: Classic Series 21mm Micro Reflex Sight with Autolive 3 MOA Red Dot Black