Red 3 MOA Dot & 30 MOA Circle Adjustable Multi-Reticle For the RMSc/407k/507k Footprints Shake Awake/Motion Deactivated Standby Up to 50,000 Hours of battery life IPX7 waterproof Side Mounted Battery Window Size - 21x16.5mm or 0.83"x0.65" Parallax Free 8 Daytime Settings/2 Night vision Settings The Cyelee CAT X PRO Micro Red Dot Sight is an ultra-compact open-reflex sight, designed for compact and subcompact pistols. It offers robust reliability, purpose-built for duty and professional use, and ready for any environment. The CAT X PRO red dot has a Multi-Reticle system allowing the use of 3 MOA red dot, 30 MOA circle, or both. Window - 21x16.5mm or 0.83"x0.65"