littleBits Electronics Coin Battery

This is one individual littleBits bit:

The coin cattery Bit is a small rechargeable power source. It can power most littleBits, but the mechanical Bits will deplete it quickly. Just flip the switch to turn it on and let power flow; when it's out of juice, plug it in with the included micro USB cable until the light goes from yellow to green. Try it with a light wire next time you go to a party!

What's littleBits? littleBits is an opensource library of electronic modules that snap together with magnets for prototyping, learning and fun.