Here's a hand-held-size rechargeable battery pack for your Raspberry Pi (or Metro, or anything else that uses 5V!). This pack is intended for providing a lot of power to a smartphone, tablet, etc, but we found it does a really good job of powering other miniature computers and micro-controllers. If you want even more power, we have a 10,000mAh power pack with two USB ports that can provide up to 2A!