This protective case slips easily and snugly over your iPod Nano and has a built-in high-capacity lithium polymer battery pack designed to extend the playback time of the 4GB player up to 55 hours, 275% more playing time than the standard playback life of an iPod. The soft silicon skin provides a firm grip and gentle protection against scratches, and the lightweight protector has a stainless steel base that guards your iPod's pin connector while allowing it to be plugged in for recharging without having to remove the cover. The leak-resistant shell resists overcharging, has slots to accommodate USB and headphone connections, and does not interfere with deft control of your iPod's functions. White or Black. 4 1/2" H x 1 3/4" W x 1/2" D. (.12 oz.)