6 Inch Dedicated Chicago Plenum housings are designed for use with all 6 Inch Nora Lighting LED retrofit luminares. CP housings are high quality, light weight units ideal for use in insulated ceilings. Airtight construction reduces energy costs by reducing the amount of air escaping through the ceiling. Rated for direct contact with insulation (except spay foam insulation) and combustive materials. Compliant with City of Chicago Environmental Air (CCEA).