The PL100 - FDLG Louvred Grille 110x54mm is manufacturedfrom (white) Polypropylene. The 110x54mm rectangular end has a minimum freearea of 5,800mm² with a male adaptor for connection inside of the System 110duct. The Louvred Grille is manufactured in compliance with Domestic PlasticDuctwork Specification DW/154 and does meet UL94HB flammability standard