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 6685-01-386-0139
NSN 6105-01-062-7554
NSN 5935-01-410-7823
NSN 5945-01-394-8377
NSN 5998-00-916-3595
NSN 6105-01-089-9143
NSN 7035-01-359-7460
NSN 5910-00-604-4693
NSN 5925-00-918-5531
NSN 6610-01-076-4800
NSN 7035-00-865-9105
NSN 5960-01-530-0581