Features: brand new and high quality Material: Nitrile rubber, features: reliable sealing and aging resistance. Pressure diaphragm of 45mm/50mm gas water heater. A good helper for maintenance of water heaters, gas valves, etc. Mainly used to increase water pressure. When the water film ruptures, it will leak. When the water volume is large, the water pressure on the water film will decrease, and there is almost no water leakage. When the amount of water is small, the water pressure on the water film will increase, but the leakage rate will be faster. The package includes: 10 pieces of 45mm/50mm size. Specifications: Material: Plastic Weight: 25g/35g Size: 45mm/50mm Color: Black Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Pressure Diaphragm