The micro knobs work with any shaft type (round, D-shaft, or T18) because they come with a tiny lil set screw. Use a 2mm hex wrench, not included, to carefully tighten once placed.This is the yellow version, comes in a pack of four! We have many other colors available as well. https://elecena.pl/product/21348874/yellow-micro-potentiometer-knob-4-pack 2022-07-29 https://elecena.pl/product/21348874/yellow-micro-potentiometer-knob-4-pack 2026-03-17