3 Waterproof Watch Screw Off Back Opener Best Wrench. Vacuum Case Opener. This is a new vacuum case opener. Made of rubber and fits in the palm of your hand. This opener was designed for opening pocket watch cases. It has two cup sizes for 0 to 18s watches. It measures approximately 3" (76 mm) in diameter x 5/8" (16 mm) in height. Suction Case Opener. This is a new suction type case opener. The suction type case opener is great for lifting the case back off of screw-back and waterproof watches after it has been loosened. The rubber tip will not scratch cases or crystals. Twisting motion applies suction to the case to open it. It measures approximately 4 7/16" (114 mm) in length 2 Prong Case Wrench. This is a new waterproof watch case wrench. It has adjustable tempered pins for easy use on water resistant cases. Its compact size makes it very convenient. This is a replacement for the Jaxa wrench. Tips adjust from 7/16" to 2 1/8" (11 mm to 54 mm). We work hard to update our descriptions and pictures of our merchandise. As part of a process of ongoing innovation by our suppliers, newer versions of the item shown may be shipped before we are able to complete an update. As a result there may be a slight variation in color and design.