Print flat side down.
I designed this for the regular flashlight because I dropped it and of all things cracked the battery cap. I imagine that this may fit other tools with a screw-on cap.
There is a bit of room inside between the cap and the battery so you may want to glue a piece of foam to take up the space, as on the original cap. In typical use it doesn't seem to be a problem; the battery holds itself in place just fine.
I made several attempts to take up the space in the model, but these all interfered with the screw functionality.
PLA does work, but PETG or some other material will probably have better wear resistance.
The author marked this model as their own original creation.