solar water heater : certification:ISO9001,ISO14001,CCC,CE,Solar Keymark solar water heater:heat pipe tube pressure:pressuriz solar water heater: material:1.volume of storage ... absorption coating5.frame:,aluminium 1.2mm thickness6.working pressure:normal working pressure:6bar,test pressure:12baradvantages:1. ... foam with thickness 50-65mm,4.Suitable for campong area,holiday residences.5.no vent ...