The Karp KSTDW Sesame Ceiling Hatch is designed for complete concealment in drywall ceilings. Door panel on the sesame door will open to check position for safety and then release for a 90° opening and is removable. The frame and the door are 20 gauge galvanized steel and the door is lined with 3/8" mineral fiberboard. The gasketing is flame retardant polyurethane. The hinge is a concealed pivot with a controlled action device (CAD), except for size 12" x 12". The Karp KSTDW Sesame Ceiling Hatch comes with wrench operated square head key. * Dimensions are H x W