... steel with 0.4mm thickness11.Magnesium rod keeps the water quality(soft water).12. Accessories: P/T valve, Mg rod, Sensor, ... you, save time.5 Specially-made We can create new model solar water heater suited to your market accord to your request.Commercial term ... :5 years for the whole system, 10 years for flat solar collector OEM service EN12975 Pressurized Stainless Steel Solar Water Heater