Attaches to your GoPro to extend battery life; Compatible with Hero3+, Hero3 & HD Hero2; Perfect for long-duration filming such as time lapse photography and endurance motorsports, etc; LCD window displays battery level and charging status; LED light display recording status; Can be charged using a GoPro Auto or Wall Charger, other USB charger or a computer; :: Unisex > iPod Accessories Size: one size.