German WWII Engineers Detonator Tester- This is a small square box measuring approximately 4 inches high and wide. Inside is a complex bakelite fuse which is very well marked. The box itself is painted gray. Interesting research project... which has now been identified. Thanks to our friend George H for sending us this information about this item:
This is a tester for a German WWII engineer's detonator (the kind that you wind up and it sends an electric charge to the detonator you wish to energize to explode). They are commonly included in the detonator leather pouch and show that the detonator will generate an electric charge when the handle is turned (by the light going on). There should be a small light on it somewhere (or I guess it could make a sound) and the two aluminum prongs fit into the threaded bolts on the detonator where the leads to the explosive would normally go.