TRUGLO TRU-TEC Compact 20mm Tactical Red Dot Sight 20mm objective lens with multi-coating for ENHANCED CLARITY AND CONTRAST; 2-MOA red-dot reticle for PRECISION AIMING; unlimited eye relief ULTRA-LIGHTWEIGHT and compact design; includes both high and low mounting bases that mount to standard picatinny or weaver-style rails ULTRA-LONG BATTERY LIFE gives thousands of hours on a single battery; programmable auto-off feature (2-8 hours); requires one CR2032 battery (included) QUICK-TOUCH POWER ON lets you tap anywhere on the optic to turn it on; digital push-button controls lets you easily adjust MULTIPLE BRIGHTNESS SETTINGS Click windage and elevation adjustments; turret caps feature a BUILT-IN ADJUSTMENT TOOL