Have 18650 batteries but a device that needs 20700? This simple adapter sleeve lets you use the smaller 18650 in a 20700 battery slot! Made from rubber or silicone, it's flexible and secure. Brand: Ijoy. Type: Forward converter (size adapter). Just slide the 18650 into the sleeve, and it fills the extra space so the battery doesn't rattle. Perfect for vape mods, flashlights, or other electronics that use these sizes. New in original packaging. Don't buy new batteries – adapt what you have. Handy for emergencies or when 20700s are out of stock. Cheap, simple, and effective. Keep your gear powered up!