Non rotating. The tube will only move up and down. Never used it in a telescope. I have one on a finder scope and the other one in an OAG. Theoretically you should be able to get it in a telescope, assuming you only use 1.25'' eyepieces.
I’ve got something similar for my telescope which I find tricky to find focus with. The helical focuser can be used as an additional fine focuser (either immediately before the eyepiece or in my cast between the tube and diagonal) so I can get a rough focus using the main focus knob and then use the helical focuser to get it sharper. Not sure if this is a rotating or non-rotating version - makes a difference if not using a straight-through eyepiece as a rotating one can move your eyepiece to poor position.
Just starting here.... can't figure out what use this would be on a telescope? Moreso for a finderscope?
Tried one of these but it blocked all the light in my 70mm Teleskop Service ED for all eyepieces. Thankfully it was a present - I didn't spend any of my money on it, but it cost £103. So this is defo Hot!... (y)