Magpul MIAD/MOE Battery Storage Core - Internal core unit for the MIAD as well as the MOE, MOE-K2, and MOE AK Grips. Designed to hold two (2) CR123A lithium type batteries in a self contained, water-resistant unit. Rubber cap is captured to the unit and can be opened with a push of the thumb. Designed To Hold 2 CR123A Batteries In A Water-Resistant Unit Sealing Rubber Cap Is Captured To The Unit & Can Be Opened With A Push Of The Thumb Made In The USA