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 5925-01-513-9924
NSN 5835-00-345-9516
NSN 5920-01-297-5895
NSN 5965-00-788-5466
NSN 6135-01-459-6424
NSN 5945-01-309-4735
NSN 6220-01-511-8878
NSN 5915-00-518-4656
NSN 6320-00-937-5625
NSN 5998-01-528-3255
NSN 5925-01-153-0144
NSN 6105-01-248-3062