ACOG 4X32 Telescopic Sight Red/Green Dot Sight 20mm Mounts Red Dot Riflescope Yellow Easily installed on any 20 mm Picatinny rail. There is no on/off switch on a red dot, but due to light sensor, the single battery will be enough for up to 45 working days Adjustable windage and elevation Powered by fiber source, providing more bright environment and reticle illumination at day. Multi-coated front lens.