With seven hours of promised life without any need for an external battery, it can be argued that this is a useful trade-off.

"There's no external battery, so there's a number of protections put into place on the system."

A small current, which then runs through the bone, is supplied by an external battery or other power source.

Nyko has you covered with its upcoming external battery.

These require external batteries in the bottom of the boat, but are otherwise practical one-piece items.

A number of manufacturers have given me external batteries, backpacks with built-in batteries.

If the combined life of external and internal battery packs is still insufficient, well, perhaps you should consider spending less time with your iPod.

Eventually, an external battery will automatically send electrical impulses to his diaphragm.

Pool broadcasts using a smartphone and an external battery.

Two external batteries allow free movement for up to two hours.