The Helios F 450 adapter is designed for connecting square ventilation shutters from the VK, RVK, EVK, and RAG series directly to round ducts or fan connectors, including the HQ/HW series. It features four corner holes that match the shutter attachment points, enabling a secure fit. The round connector is mounted onto the fan casing and fastened with self-tapping screws, providing an efficient solution for transitioning between square and round ventilation components.