We present discount for large quantity. Welcome to the touch with us! Reliable sealing and anti-aging. Good helper for water heater, fuel valve and various maintenance. Made of good materials, it may be used for a long time. Replacing the old one is a good choice. Type: Gas water heater accessories Colour: black Material: rubber Size: 54mm diameter Package Contents: 100 x stress diaphragm Only the above package content, different products should not included. Note: Light taking pictures and diverse exhibits could cause the color of the thing in the photograph somewhat different from the real thing. The dimension allowed error is +/- 1-3cm.