How to Use: Take out the lever, put it into the waterproof ring and install the lever. Specification: Item Type: Watch Crown O-Ring Material: Rubber Color: Black Applicable Crowd: Suitable for watch maintenance professionals Application Scenario: Used to keep the watch level waterproof, prevent water getting into watch Size: Approx. 1.4 x 0.6 x 0.4mm / 0.06 x 0.02 x 0.02in 1.5 x 0.6 x 0.45mm / 0.06 x 0.02 x 0.02in 1.6 x 0.6 x 0.7mm / 0.06 x 0.02 x 0.03in 1.7 x 0.7 x 0.5mm / 0.067 x 0.028 x 0.02in 1.8 x 0.8 x 0.5mm / 0.07 x 0.031 x 0.02in 3 x 1.7 x 1.65mm / 0.12 x 0.067 x 0.06in 2.8 x 1.8 x 0.5mm / 0.11 x 0.07 x 0.02in 2.4 x 1.4 x 0.5mm / 0.09 x 0.06 x 0.02in 2 x 1 x 0.5mm / 0.08 x 0.04 x 0.02in 1.9 x 0.8 x 0.55mm / 0.07 x 0.03 x 0.02in Package List: 1 x Storage Box 1 x Box of Watch Crown O‑Ring