This model features a 360-degree rotatable ring that allows you to orient the focuser (and hence your diagonal/eyepiece) to the most comfortable viewing position.
The other thumbscrew on the eyepiece end can be used to adjust the tension of the focuser to achieve a focusing "feel" that you like.
The focuser also has two large thumbscrews. The thumbscrew on the telescope side can be used to lock the focuser, allowing the use of heavy accessories or cameras without fear or slippage or losing focus.
This Dual - focuser is a great to use, focusers eliminate the annoying backlash and image-shift that plagues. You will experience very smooth and precisely controlled focuser motion.
The 2" focuser features a brass compression ring and can accept standard 2" refractor-type diagonals and other accessories. Also included is a 1.25"-2" adapter with brass compression rings and threads to accept standard 2" filters.