What replacement faders knobs will fit Xone:22?

My Xone:22 came with the B channel fader broken off, I replaced it but I do not have the plastic cap that goes over it.

In the mean time I have used one from my Mixtrack Pro (it fits), but I am selling my mixtrack pro so I need to put it back.

I've scoured all over and a Xone:22 fader knob does not seem to be around. If a mixtrack pro fader knob fits, what other ones will also fit? I could care less if it's the legit Xone:22 fader knob.

thanks!

You can use the chromacap knobs AFAIK.

You can buy replacement fader knobs off eBay. When I checked, it was like 8-10 bucks each shipped from UK so it's in your favor to buy a lot.