I ordered a few of these to replace the chrome knobs on my Ibanez GSR bass for cosmetic purposes. I didn't know much about knob sizes but after some research it seems that they all have the same size apart from some American guitars that have a different size, and luckily it's true. Easy replacement in a minute. They look great and the quality is obvious - as I was wiping my bass, the cloth stuck on one of the knobs because the friction of the knob surface was so strong. Wow. They would also fit on my Harley Benton basses, so if you want a cheap and classy upgrade, I can highly recommend these.