Schools receive MicroBit kits with a MicroBit, a battery holder and a “case” made from green paper (that can be used to hold the battery and MicroBit together). 

While useful, the paper is easily ripped, and the battery is positioned so that it gets in the way if you try to use the Edge Connector.

This print provides a more durable case, that provides some protection to the Microbit and battery pack, while leaving the Edge Connector available for use with a wide range of accessories. 

Note that the official AAA battery holder that comes with the Microbit is designed to be the same width as a Microbit. Other AAA battery holders are typically wider than a Microbit, and may not fit in this case.