The NGP GAP90-MILL-48 Fire Door Head & Jamb Gap Solution is a UL-certified, positive-pressure–rated system designed to correct excessive clearances between fire doors and frames, accommodating gaps over 1/8" up to 5/16". Rated for up to 90 minutes, this non-handed solution complies with ANSI/UL 10C, IBC, NFPA 80, and NFPA 252, and is approved for use on both hollow metal and wood fire doors. The kit includes components 9945, 9400B, and 5075B, is certified for doors with rim exit devices (per installation instructions), and helps restrict the passage of smoke. Constructed of aluminum with a mill finish, it offers a durable, commercial-grade fix for code compliance at the door head and jamb.