This product is for horizontal pipes.
When installing in the outside air intake (OA) system, dust and moisture may rust and prevent operation, so please use the OA specification damper.Directional, please be careful when installing.Install the weight arm to avoid obstructions to the rotational radius.Weight arms may interfere.Do not install this product near the fan or near the duct bend.Do not carry or install the weight arm with it.If the heat insulation material exceeds 25, please follow the instruction.The image shows the weight mounting position on the left with the wind back.If you are right please let us know