Nice clean knobs in various colours and some without a top which are listed just if you a want a bit cheaper option and dont care how they look.

These type knobs have a habit of turning Brown and thats not always because of smoke but because Bromides are leaching out of the plastic (at least thats what the book says).

These are still very grey maybe a better quality of plastic was used these are 17mm high, other mixers used a similar knob but it was a bit taller/shorter