They are manufactured with a structure of aluminium profiles or galvanised sheet metal, and covers also made of galvanised sheet metal (lacquered as an option) with sandwich finish as standard. The heating system can be electric or hot water coil. The water coil model is manufactured with copper tubes and aluminium fins, and allows the position of the water inlet and outlet tubes to be defined, thanks to the modular design of the casing. Several models are manufactured, depending on the flow rate. They can also be made to measure according to requirements. They can also incorporate regulation dampers, pre-filters and can be combined with energy recovery units.