Connections and special features of Omegon rotators The three CAA rotators have slightly different characteristics compared to the two Pro rotators. See the table below for details: Model Internal thread (usually for telescope) External thread (usually for camera/filter wheel) Optical length CAA T2 (#87375) M42*0.75 M42*0.75 13.5mm CAA M48 (#87376) M48*0.75 M48*0.75 14mm CAA M54 (#87377) M54*0.75 M54*0.75 14mm Pro M56 (#86756) M56*0.75 M56*0.75 + 2" Plug diameter Pro M82 (#86757) M82*1.0 M56*0.75 + 2" Plug diameter The Pro Rotators fit perfectly on the 2" focusers #85063, #85065 (M56) and the 3" focusers #85064 and #85066 (M82). Only adjust the small Allen screws if the rotator is noticeably too easy or too difficult to turn. They should be adjusted very precisely. The CAA Rotators are designed for light to medium-weight accessories and can be mounted wherever the connection and optical length allow.