... performance,no additives,no possibility of contamination of drinking water,ISO standard polyethylene material rated is 0 (lowest level ... be weld or fused to a fully enclosed impervious system.• lightweight,easy to install,transport,connection,sonstruction convenientand reliable ... used for siphon drainage,the same layer drainage system. Good Quanlity HDPE Reducing Tee Circulation Tee Water-supply