The origional Watch Wrench had a miner issue, immediately upon notification to the Supplier, it was immediately replaced.  The replacement unit works perfiectly. The Wrench is the perfect tool for the removal of a screw on watch back. This is three point engagement, with six different sets of engagement points, should enguage most screw type watch backs.  I would recomment both the tool and the supplier and would purchase from this supplier again.