Reliable sealing and anti-aging. Good helper for water heater, gasoline valve and varied maintenance. Made of great materials, it can be used for a long time. Replacing the outdated one is a good choice. Type: Gas water heater equipment Colour: black Material: rubber Size: 54mm diameter Package Contents: one hundred x strain diaphragm Only the above kit content, different merchandise usually are not included. Note: Light shooting and diverse displays may cause the color of the item in the photo just a little diversified from the real thing. The length allowed error is +/- 1-3cm.