Solar water heater pipe Matrial:8*1680 TP2 Superiority:good thermal conductivity.Frost resistance is good, minus 35 degrees without the cracking Useing: 1) higher heating efficiency ,advanced heat transferringmode of the heat pipe ,excellent selective absorptive coating and perfect heat preservation . 2) wide application rang , rapid absorption of heat quickly even in cloudy days . 3) independent tube makes the system reliable .As each individual tube can work indenpently and the whole project still work if some of the tubes damaged . 4) service life : more than 15 years 5) the unique connection between the heat pipe