NICOR Lighting 4-Inch IC-Rated Recessed Universal Airtight Recessed New Construction Housing (19002A) Integral thermal protector guards against improper lamping and misuse of insulation materials 6 in. height allows use in 2 in. x 8 in. joist construction Airtight housing limits the exchange of air between ceiling plenum and heated/cooled area Adjustable socket bracket assures proper and consistent lamp positioning Housing adjusts from 1/2 in. to 1-1/2 in. to accommodate ceiling thickness