This is 2.7" Jaegers focuser. It will come with the 2.0 and 1.25 adapters. It is off a 6" F8 scope. The backplate is made to fit into an approx. 6 7/8" inner diameter tube. These were never machining masterpieces, and backlash was to be expected. However, they worked reasonably well and were affordable to the amateur telesope maker.