Our exclusive battery wallets come in several types and are designed to be a AA battery holder but can fit many other sizes too. The battery contact covers are specifically designed to be used with the specific li-ion battery in each battery holders title and description and they snap on securely so that your charged battery is safer to carry in your pocket, pack or purse. The plastic battery cases, aka battery storage boxes, are great for AA and AAA batteries and come in several colors of plastic - each battery holder has its own design features too. The clear green cases will clip together to make carrying even easier. Our battery adapters are designed to convert AA and AAA batteries to size C and D batteries. Kits come in a package of two adapter sets and they are easy to use. These converters can work with NiMH or alkaline batteries.