Standard Grille for Ducted Air Systems. Simply cut a hole in your ceiling, clip in and mount. Brilliant white high gloss finish. Fits standard duct sizes of 5" dia.Adjustable -centre core is mounted on a spindle, an absolute must for whole house ventilation or heat recovery systems. Simply screw up/down the centre cone for adjusting your airflow and balancing your system. Can be used for extract and inlet air. High gloss polypropylene that is easy to wipe clean.