Internal core unit for the MIAD as well as the MOE"" MOE+"" MOE-K2"" and MOE AK Grips designed to hold two (2) AA type batteries in a self contained"" water resistant unit. Included internal spacer provides rattle free storage of either (2) AAA or (2) N size batteries (commonly used for EOTech sights). Rubber cap has two sides with marking to identify ""spent"" batteries and can be opened with a push of the thumb.