4 speed transmission reverse lamp switch. NOTE: Can use for 65 - 67 transmissions with smaller threaded back up light switch hole. Drill out hole with 12.5mm drill, 1/2 or 31/64 if you want a better "thread bite". Tap with 14mm x 1.5 tap. Washer un-threaded area of new switch with a .100 thick delrin or steel washer. ID of washer should be .550.