1. Inner tank 0.4mm SUS304 stainless steel made in Korea.
2. Middle polyurethane made by Germany Bayer.
3. Outer tank is 0.4mm color steel.
4. Frame is 1.2mm zinc-coated.
1. Whole glass vacuum tubes adopt super hard and silica glass;
2. Absorption rate: ≥ 93%, thermal radiation rate; ≤ 6%(100centigrade degree).
3. Temperature when exposed to sun without water: 250centigrade degree
4. Resist 25mm hail, life scale can last 20years.