6 sizes guitar techs use all the time
These three double-ended wrenches fit jacks, pots, switches, bridge studs, stompboxes… Just about every wrench you need for guitars and amps.

 Quality hard-plated steel

Slim enough to slide under control knobs, and into tight spaces, but tough enough for professional repair shops.

Inches on one end, metric on the other
1/2" + 14mm: output jacks on acoustics and electrics; DC input jacks on effects pedals; our flush-mount jack
7/16" + 12mm: control pots and TonePros™ Locking Studs
3/8" + 10mm: amp chassis and speaker nuts; threaded tuner bushings

6" long (152mm).