This is a quality made piece that is perhaps one of the best ways of causing a silk to visibly vanish from a glass receptacle or the bare hands.
What you have is a locking mechanism which allows the cord to be extended its full length (32") to lay in wait for the proper moment that the magician wishes to activate this strong pull by tugging on the cord to release the lock.
One must fashion a loop of strong nylon or other to the end of the cord with perhaps a damper made of a small piece of leather or rubber slightly larger than the trumpet opening of the pull. This is not all that difficult to make and once completed you will have a powerful tool in your arsenal.
Condition very good and Scarce.