... , diameter: 12mm/16mm/19mm, the length can choose according the tank capacity,100-500L.3.insulation; polyurethane foam, thickness: 55mm, can keep ... 72-80hours,4. electrical heat: inside of tank installed electrical heat use for bad weather, that controlled by ... use hot water anytime!5. the tank capacity can according your requests,and the outer tank color we can do it according yours ...