... by Lee Tongwen engineers, in order to want to match with the national standards, the provisions of the 800 caliber rubber ... design life of two years, but in general, at room temperature, and the climate is bad, you can use five years, even ... -corrosion, adaptability, and long service life. 5) A wide range of sizes and nominal diameter DN50-DN2400. The most professional Rubber Duckbill Check ...