A rigid item designed to frame a structural opening for reinforcement purposes and/or to accommodate covers, access (as modified) and doors, access (as modified).
NSN 5930-00-160-6729
NSN 6610-01-473-5678
NSN 6130-00-439-5080
NSN 6620-01-596-3252
NSN 5999-01-048-1019
NSN 5930-01-171-6198
NSN 5910-00-318-8766
NSN 5910-00-934-8855
NSN 5925-00-297-8821
NSN 7035-01-487-6481
NSN 6110-00-140-1688
NSN 5950-00-623-0241