1/4″ Guitar End Pin Jacks 2 and 3 conductor 1/4″ end pin jacks feature long threaded bushings ideal for mounting into panels and chassis up to 1.25″ thick. The metal bushing helps eliminate hum pick-up, and is ideal for musical instrument and speaker connections. Jacks mate with standard 1/4″ phone plugs and mount in a single 0.469″ diameter hole.