Halo H99RTAT Recessed Housing, 4-1/4 in Ceiling Opening, Recessed Mounting, Steel | The H99RTAT is a small aperture Non-IC AIR-TITE housing for providing accent and task lighting. The H99RTAT is designed for use in non-insulated existing ceilings. Non-IC Housing is AIR-TITE but insulation must be kept 3 in away from all sides of housing. For installation from below the ceiling.