... the widely used for its economical cost and excellent properties. 3.galvanized Steel Grating Application:Steel grating, with exquisite design and ... meeting the modern trend.The best drainage: Leakage area of 83.3 percent, more than twice of cast iron products. Hot-dip ... , 15, 20, 23.85, 25, 30, 30.16, 30.3, 34.3, 35, 40,41,60mm. US standard: 1"x3/16", 1 ...