This is the long body T-adapter. The ACC is typically used in place of the ACR for CCD cameras that can attach via T-threads and which have a short (less than 2 inches) back-focus (distance from ACC to the camera image plane). CCD's typically have a back-focus of 0 -1 inch. Sells new for $70. Asking $50 or Trade.
I'm also interested in trading for an "ATF" which holds the reducing lens for the Taurus Tracker III.