... qualityThe products are the high-strength W-SMC manhole cover and water grates researched and developed by the company ... Light WeightIt weight only 1/3 of cast-iron manhole cover, more expediently transport, install, and rush to repair, ... Chemical Construct Material Inspection Center, it has obvious anti-acid, anti- alkali, anti-corrupt, anti-aging advantages. Many indexes reached third class, longer ...