The DVR108/66 from Losmandy is a set of three mounting rings designed for use with an AutoGuider. The set includes two 4.25" (108mm) guide scope rings and a single DVR66 mounting ring.
The rings attach to Losmandy "D" style and Vixen "V" style plates via a tool-less dovetail clamp on the bottom of each ring. Once attached, the guide scope may be inserted into the rings and adjusted via three 7075 aluminum positioning screws which feature 1/4" Delrin tips.
Losmandy DVR 108/66 Specs
DVR108 Rings: 4.25" (108 mm)
DVR66 Ring: Not specified by manufacturer
DVR108 Rings: 2.96" to 4.32" (75 to 109.7 mm)
DVR66 Rings: Not specified by manufacturer