Missing parts from older T912 oscilloscope

I am missing two volts/ div knobs off an older T912 oscilloscope. Are there any knobs available that would be compatible with this scope?. I am not sure if you sell as an assembly but I appear to be missing the gray collar knob, the red "VAR" end knob, and the stem that goes back into the T912. Thanks

Sorry this has been out of support for a very long time, and we don't have alternative parts/knobs to recommend.