... tube guarante * Water tank of Non-pressue solar water heaters Outer tank material, Stainless steel Inner tank material, SUS304 ... size, 15mm/20mm* Collector of vacuum tube solar water heaters Tube size58x1800mmOuter tube diameter58mmInner tank diameter47mmGlass thickness1.6mmMaterial3.3 ... 0.6W/m2°C* Frame for compact solar water heaters Frame material, galvanized steel Frame thickness, 1.4mm thickness ...