We offer Water Heater -isi markedhigh density polyurethane foam insulation (puf) (saves 40% energy over isi norms)abs plastic body (prevents corrosion & makes it rust free)multiple safety systemstainless steel inner container (container is warranted for 5 years)electrolytic copper tank also available in select modelsexternal temperature control in select modelsavailable in 15 & 25 litres capacity