Bonjour ladies and gents of magic.  Here we have "DEADLOCK" by Patrick Reymond from Camirand Magic!!!

Condition: Very good plus.  Booklet written by David Acer.  Both written and photo instruction.

Contents: The lock and the booklet of over 19 pages.  Sorry, the cheap gold rings have long gone.

Effect: Magician introduces a padlock, opens it, then borrows a ring from a spectator. The ring is threaded onto the loop of the lock, then the lock is snapped shut, whereupon the whole affair is covered by a handkerchief. A spectator is asked to take hold of his ring through the handkerchief, such that he is certain it is safe.

The magician introduces his own finger ring, whereupon it changes instantly into the spectator’s ring! The spectator lifts the handkerchief, showing that now, locked securely onto the padlock, is the magician’s finger ring!

There are also two other effects mentioned in the book, GHOSTWRITER AND UNBILLIEVABLE.

Purchased in 2000 either from Steven's or Camirand Academy of Magic.  Wow, almost a quarter century ago.