Outside air box with air filter, heating register and sound-insulating inner lining. Electric heating register with closed tubular casing heater made of stainless steel and low surface temperature for heating the outside air to the specified target temperature. Simple operation via control element (including 10 m cable). Filter monitoring via pressure difference switch DDS (accessory) possible. Large-area M5 filter for long maintenance intervals. Flat housing made of galvanized sheet steel, thermally and acoustically insulated on all sides with 30 mm mineral wool. For servicing purposes, the cover can be easily opened using 2 safety screw caps. The device unit has protection class IP 44. Low-noise and powerful radial fan in spiral housing. EC motor/impeller unit made of galvanized sheet steel accessible for servicing purposes. Driven by maintenance-free, energy-saving EC external rotor motor in IP 54, sealed, low-noise ball bearings with long-term lubrication. The demand-based operation of an EC exhaust fan via the ALB EC remote control is possible.