It works well can achieve a sharp focus with my Sky-Watcher 100ED. When using it with the ASIAIR V1 the readout helps with repeatable focus, if you remember to zero it out before starting( I haven’t tried with any other control software)Which is the hard part for me. Unfortunately if you use the hand paddle because there is no encoder the readout doesn’t change in the ASIAIR so it’s either or not both. You can use both then the position readout is useless. I wish it also had more speed settings, I think the hi speed is too slow, but that’s just my opinion. There was no clear instructions about where to plug in the hand paddle, it’s the same place the temperature probe goes so again it’s either or has to which to use.
Having given up on waiting for this item to be available through OPT I ordered it directly from ZWO after receiving assurances that it would fit my William Optics ZS61 scope. The main problem was determining how to remove the left hand focusing know. I found that the set screws are accessible through two holes (blocked by screws) near the left edge of the mounting block. Once the know was removed it was just a mater of choosing the correct coupler and securing the mounting bracket. Since this EAF did not come with a hand controller the only way to move the focus of the scope requires connecting to compatible software. Both ASCOM and INDI drivers are available, but using the ASIair for control is pretty transparent. I have also found that it works well with Ekos / Stellarmate and with AstroImager. Many other astroimaging apps are said to be supported. Be sure to calibrate and verify the position of perfect focus. I recently received a second EAF from OPT that I intend to mount on my WO FS98. I did discover one caution with the hand controller. Be sure to push the connector in firmly at both ends or the EAF does not function. Also, the thermometer appears to function properly but I have not had a chance to make use of it. In summary, this is a very well built unit with an elegant design that makes it adaptable to many small telescopes. A 5 kg. load capacity seems more than adequate for most cameras on small scopes.
Fit perfectly on focuser of my Sky-Watcher 72ED. Using with N.I.N.A. and was able to connect everything just fine and had a successful imaging session.