Thought I'd post this here also. I'm selling an AP 2.7" adapter to SCT threads (ADA204 - $40 new) and an SBIG T-thread visual back ($49 new) - see photo in CCD area. These threaded connections end the fear of dropping your camera off the back of your scope because a set screw slips, it is a very positive connection. These are both like new, just a few months old, and I'll ship them to you (conus) for $75 (or make offer). Here's a picture that shows them connected and on an extension tube (not included) if it is not clear how they attach. I'd prefer to set them as a set.
Thanks for looking!