CVLIFE Micro Reflex Sight Red Green Dot Scope Sight with QD Quick Riser Mount and Additional Rail Attachment Adapter Field of view (@100 yards): 50; Objective aperture: 22mm; Rail size: 20mm, Length: 68mm, Width: 40mm Unlimited eye relief. This sight can be easily used with both eyes open, increasing the awareness of the surroundings and providing faster target acquisition for shooters. Red and green two illuminations, 5 levels of brightness allow shooters to find the perfect brightness needed for the environment, lighting, and weather conditions This red and green dot sight comes with a quick detach high profile mounts and a low profile picatinny mount. Easy for sight remounting. There is no need for centering due to the parallax free design.