1.3years guarantee,15years lifetime 2.Stable performance 3 large quantity of hot-water supply 4 CE ISO9001 Sun Storm stainless steel non-pressurized solar water heater1. material of inner tank: SUS304-2B 0.40MM thickness2. material of outer tank: stainless steel3. bracket material: stainless steel 1.50MM4. heat preservation: 72-80h5. insulation : 55MM foaming6.Assistant tank: 5L, 8L, 10L, 12L7. ...