The Holosun HE403C-GR Micro Green Dot Sight is designed with 6061 aluminum construction that provides waterproof and fogproof protection, and the 2 MOA dot reticle helps you improve your accuracy in the field. Shake Awake technology powers the optic on with slight movement of the unit, which may be installed on various firearms such as shotguns, pistols ,air rifles and crossbows. Compatible with standard mounts.