47 mm vacuum tube outer diameter 1800 mm tube length 480 mm outer tank diameter 100 liters to 500 liters tank volume Puf 50 mm tank insulation (polyurethane foaming) Stainless steel grade 0.5 mm inner tank Seam less and non welding technology method Silicon rubber type of grommets 5+2 yrs warranty Website http://renergyindia.com/