The duct to wall flange provides a clean and tidy connection, used to join ducting to your outlet point.
The duct to wall flange is screwed into, or glued onto, the area around the outlet point in your extraction system. The rim can then be used to attach ducting using a duct clip or duct tape.
To mount the duct to wall flange, start by drilling enough holes into the flange area to ensure it can be properly secured to the wall. This should always be carefully undertaken by somebody with the appropriate skills. Then, screw it into place, so that it sits flush over the outlet point. Ducting can then be fitted over the rim using a duct clip.