The pack contains converters and AA multiusage+ Ni-MH batteries for you to turn the AA batteries into D batteries in a snap. These 2 in 1 batteries are 100% compatible with all your D battery devices. MultiUsage+ Ni-MH Rechargeable Batteries can be charged up to 500 times or more and hold their charge with long storage life. Pre-charged and ready to use. Specifications: 1.2V