Truglo's 30mm Crossbow Red Dot sight features click windage and elevation adjustments and an integrated Weaver-style mounting and lanyard system. The lanyard system helps to prevent loss of screw-down W/E caps. It comes with see-thru flip-up lens caps, is optical-quality, and is water and fog proof.When shooting at close or medium ranges, a red dot sight is a great option for crossbow hunters. The 30mm Traditional offers unlimited eye-relief, a wide field of few, and a compact design that are not available in magnified optics. Features: Descending diameter dots reticle for multi-distance shooting (smaller dot for longer shots) Unlimited eye relief Wide field of view Flip-up lens caps/lanyard system Lightweight compact design Easy to mount Integrated Weaver style mounting system