Secure fit: a dedicated slot to fix the battery in place, ensuring stable power delivery and reducing movement during use. Four piece professional adapter set: the battery holder is a set of four battery adapter convert cases designed to convert any battery size to C size for use. Just put batteries into the convert, and it will function the same as a Csize battery. Wide compatibility for electronics and various situations: suitable for devices that need a Csize battery, giving you flexible power options in many contexts. Small and portable: the battery convert box is compact and easy to carry, ideal for onthego use. Use scenarios: Power devices that require C batteries when only other sizes are available, such as flashlights, radios, and certain toys. Convert AA or AAA batteries for remote controls, portable lights, and hobby electronics that use Csize power. Include in camping, travel, or emergency kits where carrying multiple battery sizes is impractical and flexibility is important.