Tiny Flat Knob for LED Dimmer

Tiny flat knob for LED dimmer. Has internal 18-point star shape. For a 1/2" hole through 1/2" plywood.

For this dimmer: https://www.amazon.com/Dimmer-Switch-Channel-Controller-Lighting/dp/B078X4V86C/ref=as_li_ss_tl?dchild=1&keywords=12v+dimmer&qid=1597679029&sr=8-19&linkCode=sl1&tag=ktgthing-20&linkId=93242d135a3e81d1ac31d9df71a6c2a4&language=en_US (affiliate link)

This is for the USB-C powered bookshelf reading light project here:
https://www.youtube.com/watch?v=IknwR1jWbqI

(if link doesn't show, search "Bunk Bookshelf Reading Light" on YouTube. Or my channel Keith's Test Garage)