Keychain battery container for Dana R/RS batteries

Owners of a Sooil Dana R/RS insulin pump sometimes face a sudden battery alarm. It helps to always have one with you, so this is a small keychain case that can be opened with the same tool that you need for opening the battery lid on the pump (or something like 5 Euro-Cent coin).

Designed for fitting tightly around the battery, printed/tested with default settings on a Prusa MKII, 0.15 layer height.