The all-new Gen II ERGO O-Grip features a threaded grip cavity that can be utilized for the storage of a spare battery or small parts with the use of our 4115 End Cap Plug. The advantage of a threaded plug is increased security under recoil and adverse conditions. Like the original O-Grip, the Gen II O-Grip also features built-in channels that can accommodate the installation of a variety of different sized grip bands, increasing the texture and traction based on the shooters needs.Features :Nylon 12 ConstructionInterchangeable Rubber RingsThreaded grip cavity for the storage of a spare battery or small parts