... 2.Import equipment laser welding 3.A test certificate compact solar energy 1.Inner tank: SUS304 food grade stainless steel ,thickness ... 0.5mm2.Outer shell: stainless steel 0.4mm3.Solar collector: black chrome or blue titanium 4.Frame: use ... solar controller6.Features: heat collect fast, looks nice and install very convenient, but is not fit for very cold area compact solar energy ...