Additional Details ------------------------------ Product description: PRODUCT DESCRIPTION: Save time and money by replacing the need for multiple battery sizes with battery converter shells. Stock up on AA batteries and never worry about buying C or D batteries, you will have no need to purchase or search for different battery sizes in your home. These battery converters are incredibly convenient and easy to use for anyone, there are no complicated instructions or procedures to perform for setup.We strongly recommend the use of high energy Alkaline or Nickel Metal Hydride (NiMH) AA batteries within the converters. ABOUT POPULAR MECHANICS: Since 1902, Popular Mechanics has been the authority on how your world works. Our Mission at PM Gear is to bring our audience cool and unique gear, gadgets, innovations and inventions across the automotive, home, science, technology, and outdoor spaces. Popular Mechanics is about wonder, about being curious about the world around you, and it?s about getting your hands dirty, too. Our vision is to create technology products for people who love to tinker with their tools.