1Bergeon Rolex® Case Opener 13 Aug 2015 /0 Comments/in Watch Tools This Bergeon case opener is used for opening waterproof and grooved Rolex® and other oyster watch cases. Contains wrench and six Bergeon grooved chucks in the following sizes: 18.5, 20.2, 22.5, 26.5, 28.3 and 29.5 mm.