1.Certified by Solar Keymark. 2.24mm heat pipe 3.Nick coating heat pipe 4.working pressure :0.6Mpa 5.Made in China solar water heating systemHeat pipe solar collector, solar collector, solar thermal panel, solar water heater system, 1) Collector channel: Cu pip 2) Collector crust: Aluminum alloy 3) Tube with 58mm dim, 1.8m length or 47mm dim, and 1.5m length 4) Water capacity: 150L / 200L / 300L ...