RMDL sealed long frames are designed similarly to the RM
mounting frames to accommodate an air supply or exhaust
valve. The difference is a longer inward sleeve for a more
stable fit when installed.
The longer inward sleeve also helps adjusting the end length of
the ventilation ductwork: the mounting frame can be fitted in
the duct in a range of depth levels to compensate the end length.
The seal provides air tightness class D according to PN-EN-12237.
