The cuff is screwed onto the end of the hose that fits into the wall inlets. The metal ring on the cuff will activate the system by contacting the 2 spring loaded metal pins in the wall inlets.
This product screws onto the hose in an anticlockwise direction as its a reverse thread.
If you have a switchable hose the cuff is already built into the hose so this product cannot be used as a replacement.
 
Some very old wall inlets had depression switches instead of the contact pins. If you are concerned as to what you have please give our office a call.