Moonlight focuser with high resolution stepping motor (including adjustable slip clutch) and extension flange with SC back thread.
I just checked the manufacturers web page and the replacement cost including shipping to Australia came back at $740 (Aus)
Here's one with very little use and in excellent condition for half price,
$370
The action of the draw tube and rotation flange are buttery smooth without any hint of play or slop. It allows you to (manually) rotate your camera for framing or guide star selection without losing focus.
https://www.dropbox.com/s/x25638s6gs...506_095551.jpg
https://www.dropbox.com/s/sl84xkh1vc...506_095608.jpg
https://www.dropbox.com/s/tgthrlt519...506_095627.jpg