Halo, 4", Insulation Contact Recessed Housing, New Construction Recessed Housing, Air-Tite, For Use In 2" x 6" Construction, Integral Thermal Protector, Junction Box Listed For Through Circuit Wiring, 4 Each 1/2" Knock Outs, 4 Each Non-Metallic Knock Outs, Pry Out Slots & Strain Relief, Pre-Installed Nailless Captive Bar Hangers To 24" Joist Span, Fit To T-Bar Spline, Hangers Repositioned To 90 Degrees Without Tools, 5-1/2"H x 4-1/2" Opening, UL, CSA, Damp Locations, IP Rated, UPC Bulk.