Reproduction disposable German 4.5V flashlight batteries. This flat type battery was used with many variations of flashlights and even in many bicycle headlights. These are built around brand new batteries and are not rechargeable or refillable. In testing, the batteries lasted over 12 hour of continuous use but did start to dim after about 6 hours. So it should hold up for several reenactments at least if you are using it normally and not as a lantern.
The battery has a black plastic case that has been almost completely covered in brown paper before the label was added.
Our labels are printed nearly the same way they would have been during the war. We use an ink that will NOT bleed when wet. The art work was carefully restored to make the printing plates and then the act of printing them produces similar small variations and errors that would have occurred on original labels. They don't look like glossy laser printed labels or ink jet printed home made repros; they look practically original.