This advantage of the Newtonian Crayford design focuser, constructed of strong aluminum with a black anodized finish, the drawtube glides on 4 bearing wheels with 40mm travel, a built-in tension knob for adjusting the "feel" to match your preference to gives zero image shift and zero backlash, offer ultra smooth and finely adjustable.
The friction can be adjusted with a large thumbscrew, a second thumbscrew can lock the focuser tightly in position. Feature 2" brass compression ring, adaptor from 2" to 1.25" with brass compression ring and 2" filter thread.
The features: 
Load capacity up to 2.7kgs 
Ultra smooth focus motion
Constant movement
2" compression ring
2" to 1.25" adaptor with compression ring and 2" filter thread