1.ISO9001:2008 quality systems 2.4 running lines. 3. Delivery:7-30days 4.Availability:20,000tons/year Trench coversUnique features:1.Attractive appearance : clear and smooth figure, silvery appearance, modern-styled.2.Optimal drainage: Leaking area can reach 83.3%, which is as twice as cast iron.3.Galvanized surface: rust-proof, anti-corrosion,Maintenance convenient.4.Economical: much more ...