The vapour barrier extender is for use with Liteline 3½ and 4 retrofit IC fixtures that are approved for insulated ceilings, to prevent air leakage from the living space into the attic. Suitable for insulated ceilings. The body is constructed from a membrane with flat flange all around. Can be inserted into insulated ceiling after drywall is installed. Material is UL listed to 90°C. Required to be installed in order to comply with specific National Building Code of Canada (NBC) regulations.