Not required., Enthalpy counterflow heat exchanger (polymer membrane)., Combination counterflow heat exchanger (polymer membrane)., Hygrostat (wall-mounted)., Capacitive return for motorized exhaust and supply air dampers., Electric preheating surface., Electric comfort heating surface., Water heating surface., Condensate pump., PIR/motion sensor (wall-mounted)., PIR/motion sensor (built-in)., CO2-sensor (wall-mounted)., CO2-sensor (built-in)., TVOC-sensor (built-in)., CO2-/TVOC-sensor (built-in)., Energy meter., Cooling module, CC (only for horizontal model)., Wall-/ceiling bracket., Ceiling frame., Airlinq® Viva control panel., Airlinq® Orbit control panel., Airmaster Airlinq® Online., Airlinq® Online API., Airlinq® BMS., LON® module., KNX® module., MODBUS® RTU RS485 module., BACnetTM MS/TP module., BACnetTM /IP module., Mini B USB (on front of unit).