... The professional manufacturer of siphon,drainage,ground source. Black HDPE pipe is good for anti-UV, anti-aging, anti ... -corrosion.The useful life of HDPE pipe is more than 50 years.wall is smooth, ... for long-term using.• polyethylene pipe can be weld,fittings and pipes into one,without the possibility of joint ... used for siphon drainage,the same layer drainage system. HDPE Socket U tee