Reliable sealing and anti-aging. Good helper heater, gas valve and various maintenance. Made of superb materials, it can be used for a long time. Replacing the old one is a reputable choice. Type: Gas water heater kit Colour: black Material: rubber Size: 54mm diameter Package Contents: a hundred x stress diaphragm Only the above kit content, different item should not included. Note: Light and assorted displays can cause the color of the object within the photo somewhat different from the genuine thing. The measurement allowed error is +/- 1-3cm.