With heat recovery (warm exhaust air heats cold fresh air). G4 filter (F7 or activated carbon on request) Aluminum heat exchanger (Heatex) with turbulence surface .415x415x500x3.3mm Stainless steel housing (insulated) Infinitely adjustable (rotary knob) On request also with 2 exchangers in series for even higher heat recovery (up to 95%!) We ask for a delivery time request as we also sell outside of Ebay We manufacture these devices to measure! (According to your specifications) Up to 84% heat recovery, with an output of 100m³ (in winter with condensation) Calculations according to din , without the fan waste heat (increases the efficiency) Performance data at full load 65% in winter with condensation, 55% in summer If you have any questions, please contact us. Contact details are in.