The industry standard for output jacks. These Switchcraft jacks accept standard 1/4” plugs. A mono jack is suitable for most guitars; a stereo jack can be used for stereo wiring, or to enable onboard active electronics when a 1/4” mono plug is inserted. Required mounting hole diameter: 3/8” (9.53mm). Thread: 3/8 x 32. Thread height: 1/4” (6.35mm). Mounting nut and flat washer included.