Borg 7841 Helical Focuser with m42x1 (Pentax) threads male on one end and female on the other. See here for more details:
http://www.sciencecenter.net/hutech/prices/focuser.htm
I was using this briefly on my spectroscope to adjust the camera position wrt the grating. It is in new condition except for the set screws marks on the outside of the barrel.
120$ shipping included