This kind of solar collector has past SOLAR KEY MARK EN12975 TEST

Tank Materials:
Inner tank: SUS 304
Inner tank materials: 1.2mm
Outer tank: Colored steel
Outer tank thickness: 0.37mm
Insulation: Polyurethane
Insulation thickness: 50-65mm
Heat exchanger: Copper coil
frame: Steel coated with the zinc
frame thickness: 1.5mm
Advantage: Get the instant and healthy hot water at any time.
Pressure operation.