Being lazy to change battery on your wireless mouse, keyboard, camera external flash, gadget and toys. Don’t worry, a rechargeable batteries have the solution to solve your problem but they need to be re-charge at the 1st before you can used, sometimes luckily they come with pre-charge but not fully charge. But it’s better than normal alkaline batteries which more expensive and lack of re-usable again and again. Mostly re-chargeable batteries can be charge 1000 times in the cycle of its lifetime. Price depend on the charge capacity and brand, Fujitsu, Sony, Panasonic are the best manufacturer that you can select for rechargeable batteries. It’s come in AA, AAA size and other 9V if applicable, need to visit nearby store or buy online at home and wait few day for the purchase item at your home.