Circular Air Duct Heaters are intended to heat fresh or recycled air moving in industrial processes or in air-conditioned buildings. They are developed and created either as a standard product or as a custom solution. They have U-shaped or finned heating elements placed on mounting plates, shielded steel or stainless steel cases, or both. Circular Air Duct Heaters can be installed between flanges above an air vent, inserted in a drawer, sleeve, or case, and have a rectangular or circular cross-section.