The HS403B is a small compact micro red dot optic with durable and reliable construction, unaffected by extreme weather conditions. The top mounted buttons allow for easy operation without obstructing the user's vision. It's designed for day and night use with 12 settings (10 Daylight + 2 NV) for the reticle to match the ambient lighting conditions. The sight will remember the last saved brightness setting when powered on and off. Features parallax free optical system, unlimited eye relief and shake awake technology that powers the optic on with slight movement. The green LED allows up to 50,000 hours of operation on one CR2032 battery. It may be installed on various firearms such as shotguns, pistols, air rifles and crossbows. The HS403B is compatible with standard mounts, a low mount and 1/3 Co-witness mount included.