1.Reasonable price and high quality 2.Country of origin 3.On-time delivery 4.10 ys experience manufacter 5.quick ... the catalyst and prolong the operating cycle of the system. As the impurities present in the materials are different, the user ... grade, but 12 sizes by reference to the diameter, such as Φ3,Φ6,Φ8,Φ10,Φ13,Φ16,Φ20,Φ25,Φ30,Φ38,Φ50 ...