Circular duct heaters are intended for installation in ventilation systems to increase the temperature or to keep it at a constant level. The ducts are made of galvanized steel, ALU-Zinc or stainless steel. Dimensions Ø100-1000mm, the heating elements are of stainless steel. Galvanized models in standard range available from 250W – ± 6000W optional with (thyrister)temperature control and maximum protection.