New Adjustable Watch Case Opener. This is a new watch case opener. This is the best case opener I have ever tried. It was developed by professional watchmakers as a safe method to open snap-on case backs. The blade adjusts to accommodate the diameter of your watch. With the turn of a knob, the blade moves closer between the case and case back for easy removal. It is used to open the toughest watches without scratches or damage to the case and crystal. This unit can also mount on a bench top.