The closed emitter design shields against all elements for peak performance in any environment. It features a user-selectable 3 segment reticle with 10 Day/2 NV brightness settings allowing you to customize visibility for every scenario. Setting 5 gives you an impressive 25,000+ hours of battery life, complemented by automatic and manual brightness control along with a convenient Shake Awake feature. The recoil block ensures alignment and zero hold. Water and dust proof rated.