vaccum tube solar heater with SOLAR KEYMARK,ISO,CE,SGS Copper coiler inside of tank could bear high hydraulic pressure water vaccum tube solar heaterMaterial:Inner ... 0.31mmBracket: galvanized steel, δ1.5mmInsulation: polyurethane frothing, δ50mmVacuum tube: tri-elements coating, 58×1800mmAccessories: water auto-feeding tank, ... hydraulic hot water out from the coiler. vaccum tube solar water heater