The Viridian RFX35 Reflex Red Dot Sight is designed from the ground up to ensure clarity, solid function, and rapid target aquisition. Everything users need from their most reliable handgun optics. With INSTANT-ON technology this red dot wakes up when you pick up the gun and will automatically shut off when you put the gun down for storage, maximizing your battery life and giving you and instant sight when you need it most. Tested in the harshest conditions, the Viridian RFX35 Reflex Sight is sure to be ready whenever you need it. FeaturesRMR FootprintAuto On/OffCompatible with Full-Size Hangduns, Shotguns and Rifles10 Brightness Settings (8 Day/2Night)22mm x 26mm Window