5/16" hole

The spigot end that fits into your head is 1

which is metal as well

Fits 1978-up Wide Glide

5-inch wide removable mounting straps with reflective stitching offer mounting options and security

Mini Push Button Switch - Brass Length_2" 5/16" holeThis universal mini push button switch is ideal for use on your handlebars to keep your kit clean. It can also be used on a battery box, gusset, top motor mount, or anywhere you can stash it. The 12 mm (. 47") round push button switch includes a special radius shaped spacer to allow clean mounting in handlebars. Great for turn signal, starter, horn, stop or hi low operations (must be used with a relay). Includes two 20" wires; installing requires 9