New Pocket Watch Knife Screw Off Cases. Case Opening Knife. This is a new case knife opener. This steel knife is designed to open all kinds of snap back watch cases even Bergeon types. It measures approximately 4 1/2" (115 mm). Pocket Case Wrench. This is a new pocket case wrench. This tool has adjustable metal teeth for use on watch case backs. The tips adjust from 9/16" to 2". Snap Back Case Opener. This is a new snap back case opener. This is a cylindrical spoon-shaped tool. It is designed to open practically all types of cases with press backs. This tool lifts snap type watch case backs, easily popping off even the most tightly closed.