Features: 1) Supporting frame: 1.5mm Alumunium zinc alloy coated steel, 2) Outer tank material:zinc aluminium steel plate, endure high pressure, defend cauterization 3) Inner tank material: SUS304-2B food grade stainless steel plate 4) Isolation layer: 55mm polyurethane foam, long-time prevent frostbite and long-timeheat-preservation 5) Water temperature / Water lever display 6) Water capacity: 100L,150L, 200L,300L((optional) 7) Type: 15, 20, 25, 30 tubes (optional) 8) Tube size: Use 47mm dia x 1,500mm high quality vacuum tube, it can absorb 95 -98% sun-light 9) Temperature preservation can last for 72 - 85 hours producing area:China