Features: 1Install waterproof O?ring to the watch or replace the waterproof ring, ensure the waterproof function of watch. 2Contains 90 different sizes of the waterproof ring, suitable for different watch types and watch model to use. 3Included storage box makes your articles not easy to lose and more convenient to storage, convenient to use. 4One of the professional watch repairing tools, suitable for repairmen and amateurs to save expensive repair costs. 5Small and convenient, easy to carry and convenient transportation, exquisite workmanship, no scratching for watch. Item Type: Waterproof O Ring Material: Plastic Applicable People: Watch maintenance professionals Application Scenario: Used to add waterproof ring to the watch or replace the waterproof ring Width: Approx. 0.9mm / 0.04in Double Ends Diameter: Approx. 17.34 x 18.5mm / 0.68 x 0.73in17.84 x 19mm / 0.7 x 0.75in 18.84 x 20mm / 0.74 x 0.79in19.34 x 20.5mm / 0.76 x 0.81in 20.34 x 21.5mm / 0.8 x 0.85in20.84 x 22mm / 0.82 x 0.87in 21.84 x 23mm / 0.86 x 0.91in22.34 x 23.5mm / 0.88 x 0.93in 23.34 x 24.5mm / 0.92 x 0.96in26.34 x 27.5mm / 1.04 x 1.08in 34 x 28.5mm / 1.34 x 1.12in30.34 x 31.5mm / 1.19 x 1.24in 27.8 x 29mm / 1.09 x 1.14in30.84 x 32mm / 1.21 x 1.26in 28.34 x 29.5mm / 1.12 x 1.16in31.34 x 32.5mm / 1.23 x 1.28in 28.84 x 30mm / 1.14 x 1.18in31.84 x 33mm / 1.25 x 1.3in 18.34 x 19.5mm / 0.72 x 0.77in29.34 x 30.5mm / 1.16 x 1.2in 19.84 x 21mm / 0.78 x 0.83in24.84 x 26mm / 0.98 x 1.02in 21.34 x 22.5mm / 0.84 x 0.89in25.34 x 26.5mm / 1 x 1.04in 22.84 x 24mm / 0.9 x 0.94in25.84 x 27mm / 1.02 x 1.06in 1 x Storage Box&nbsp 90 x&nbspWaterproof O&nbspRing