If your here, you are no bought interested in watches - safe bet.  And if you're here, you're also no doubt interested in tools like this case back opener, used to open and close the case backs on watches - vintage or modern.
 
This case back opener comes with pin sets for opening different watch case back styles, and features a knurled handle with adjustable thumb wheel that adjusts the tool to accomadate various case dimensoins, from 18mm to 32mm.
 
This watch case back tool measures 5.5" x 2" inches.