This print was born out of a need to organize recharchable batteries for use with photography flashes such as the Canon 580 or 430. It holds 4 AA batteries and indicates whether they are charged or used based on how the two halves are oriented. One piece has a full battery icon on one side and an empty battery icon on the other. The other piece has an arrow icon that points to whichever battery icon indicates the current charge. The two halves can be held together by a rubber band fitted around the grooves, if the fit is not snug enough to hold them together.
There are two parts to print. My version was printed on a Cupcake with a Mk6 extruder. The interior walls are thin, so may have threads or may even be partial. I also sized them larger than the diameter of most batteries to account for shrinkage. However, when printed, the fit was nice and snug, and a little clean-up with a hobby knife was all that was needed.
Sketch-up files included for your modding pleasure.