Housing: .026 23ga galvanized steel. cULus listed for direct contact with thermal insulation. Airseal® housing minimizes air leakage to less than 2 CFM at 1.57PSF (or 75PA), which complies with Title 24, the International Energy Conservation Code, and Washington State Energy Code (Section 502.4). This reduces heat loss and condensation in ceiling. Access door for inspection of junction box. 2. Lower frame and top cover: .026 23ga galvanized steel. Accommodates ceilings up to 1 5/8 (41mm) thick. 3/8 (9.5mm) deep integral lip with four notches at 90° apart to simplify alignment. Locks into position along length of mounting bars with locking screws. Indicator lines on housing top and sides to simplify alignment. 3. Retaining clips: Permit easy and fast installation of light engine junction box: 2 1/2 (64mm) x 5 3/8 (137mm) x 2 (51mm) .032 21ga. Galvanized steel. cULus listed 90º C supply conductors. Rated for branch circuit wiring supplying connected luminaires (daisy chaining).