Rittal's latest TopTherm air-to-air heat exchangers for enclosure cooling come in three sizes, each of which can be easily upgraded simply by replacing the heat exchanger module. For example, modules of 30, 45 and 60W/K capacity can be slotted into just one case size. The new products cover capacities from 17.5 to 80W/K and are based on the unit sizes and cut-out dimensions of Rittal's existing TopTherm range. The units have two separate air circuits and can be internally or externally mounted on either the enclosure wall or roof. Internal circuitry is protected to IP54 and thermal winding protection on the fan motors is also provided as an additional safety measure.