Meprolight 901142372: Our advanced closed emitter design shields against all elements for peak performance in any environment. It features a user-selectable 3-segmentreticle with 10 Day/2 NV brightness settings allowing you to customize visibility for every scenario. Setting 5 gives an impressive 25,000+hours of battery life, complemented by automatic and manual brightness control along with a convenient Shake Awake feature. Plus, the recoil block ensures alignment and zero hold. It is IP67 water/dust proof rated. This durable optic is built for precision.