Cuff screws onto the threads of the Basic Hose (counter-clockwise). Also very helpful for maintenance of a central vacuum system. When inserted into a vacuum inlet the suction starts right away so it is easy to test all the inlets and to cuff with the hand, which builds pressure and helps clear out debris and clogs. The insertion end is just under 1-1/2" wide OD, and the screw-on (threaded) end is 1-7/8" wide OD.