The MIAD/MOE Battery Storage Core is an internal core unit for the MIAD as well as the MOE MOE+ MOE-K2 and MOE AK Grips. It is designed to hold two AA type batteries in a self-contained water resistant unit. Included internal spacer provides rattle free storage of either AAA or 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. Made in the USA.