... absorption rate; antifreeze, antihail 2)good heating result Storage tank:1.tank capacity (L): 100,150,200,260, 300,400 ... 5002.inner tank material: SUS304-2B, thickness (mm): 1.0, 1.5, 2.0,3.outer tank mterial: color steel4. ... 504.manifold casing material: 1.6mm aluminum5.bracket material: 1.5mm galvanized plate/aluminum6.heater pipe material: 1.2mm thick copper7.insulation layer: polyurethane8 ...