All Parts EP 055L-000 1/4-Inch Input Jack, 3/8-Inch Bushing
1/4 Input Jack, Switchcraft, With 3/8 Threaded Bushing, With Nut and Washer. Requires 3/8 Inch-diameter mounting hole; 3/8 x 32 threaded portion is 1/4 Inch long (EP 0055L-000 Shown in Picture)