The DRS (Defendu Reflex Sight) is so versatile and effective at close range, we've named it after the famed Lt. Colonel William Ewart Fairbairn whose Close Quarters Combat system was designed to rapidly disable an opponent with potentially lethal force. Perfect for tactical operations or home defense, the 1x reflex sight offers three reticles calibrated for speed and accuracy at 7, 25 and 50 yards. The ultimate CQB sight, it is built with Steiner's legendary ruggedness. Lightweight, compact and simple to use. Window size is .96 x 1.26 in. (height x width). The overall height is 2.57 in., and it sites 2.35 in. above the rail. The C2 reticle has three options (see image in photo gallery): a. Singe dot b. Dot and stadia lines c. Dot, stadia lines and close dot