I bought this to try and fix the issue with the stock focusser where it impedes into the OTA by over an inch when using the Skywatcher coma corrector and using it for astrophotography. That leads to horrible star diffraction issues.

So far I can confirm the following:

* It fits the 200PDS as the holes are in the right place.
* it doesn't come will bolts or nuts so you have to use the existing ones, but they work fine.
* it does leak light from the sides, so you will have to fix that yourself. Black insulating tape works fine and takes 5 mins to apply.
* A ZWO EAF does fit, but the flexible coupler is a "really" tight fit .. I had to use super lube to get it running smoothly. The same flexible coupler is needed as the stock focusser, so that makes it easy (i.e. the 5mm to 4mm coupler).
* at prime focus, the focus tube barely enters the OTA (maybe a couple of mm). Job done as far as I am concerned.
* the extending focusser tube mechanism means visual is still possible (if that is your thing).
* with the EAF you'll need to redo the settings (particularly the limits) as there is much less travel with this focusser tube.

So far, so good ... just need a clear night to test it.

Faultless construction, superb silky finish. Knobs chunky enough for use with gloved hands. It weighs in at just under a kg, so not a lightweight product. Very smooth movement.