These round white plastic exhaust/supply grilles have easily adjustable
airflow adjustments that will diffuse air evenly and quietly throughout
a room. The grill can simply be inserted into the end of an appropriately sized rigid duct, or used with flex duct with the optional mounting collar. Each grill/diffuser is manufactured of high quality flame retardant polypropylene plastic that will not discolor over time. The optional mounting collars are used to secure the duct work to the ceiling joist where it pentrates the ceiling.
