The D4X-IC1A-R series is designed for insulated and airtight ceilings. A black powder coated 20 Ga. cold rolled steel baseplate and a 18 Ga. galvanized steel junction box with multiple K.O. allows for easy wiring entry. The housing series is approved for branch circuit wiring. Perfoming in accordance with ASTM E283-91, the airtight option also meets the requirements of “having no more than 2.0 CFM air movement from the conditioned space to the ceiling cavity” (Sec. 502.4 of 1991 WSEC- Washington State electrical code).