Electric Guitar Jack Wrench
This is a tool to tighten the 7/16" nut which holds the amp jack in place on many electric guitars. Tighten with your fingers or use the slot to turn the wrench with a flat head screwdriver. This is also a solution for jacks that have fallen into the guitar body after the nut has loosened and fallen off. You can pull the jack out of the body and hold it in place while re-threading the nut by using a thin wire or hook through the screwdriver slot and down the center of the wrench.