Designed as a quick detachable vertical grip, it features an internal waterproof storage compartment for up to three lithium 123 size batteries. The BVG Grip mounts on Picatinny and Weaver rails. The BVG is easily installed, or removed, by use of a internal threaded tension rod that securely positions the grip in your choice of location upon the rail. The batteries are secured inside the waterproof battery compartment utilizing a plug with an o-ring. This compact grip provides a comfortable feel in your hand and helps to prevent muzzle rise and provides waterproof storage of batteries for your optic or lighting systems.