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 5935-01-198-8998
NSN 6105-00-409-4162
NSN 5835-01-074-7593
NSN 7035-01-091-7481
NSN 5935-01-617-1349
NSN 5975-01-588-7234
NSN 6110-01-195-3353
NSN 6220-01-602-9275
NSN 6610-01-275-9771
NSN 5835-01-426-6573
NSN 6220-01-401-5337
NSN 5930-00-446-3263