The Helios RVM 225/DRVM 200 motorised damper is engineered to stop cold air from entering horizontal fan systems. It opens automatically using a motor and features a cylindrical housing made of sheet steel with mounting flanges on both ends. The unit can be directly fastened to the fan’s base plate, with pre-drilled holes compliant with DIN 24155, page 2. Lightweight aluminium flaps ensure smooth airflow control, while polymer buffers enable quiet operation. A 0.9 m connection cable is included, and it is recommended that the electrical wiring be connected in parallel with the fan for optimal function.