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 6645-00-618-9496
NSN 5835-01-080-7784
NSN 5996-00-617-1676
NSN 5855-01-627-4702
NSN 6145-00-050-1484
NSN 5985-00-953-9128
NSN 5925-01-195-7258
NSN 6150-01-040-0335
NSN 5990-01-040-6358
NSN 6620-01-484-1303
NSN 5905-01-065-5333
NSN 5835-01-576-5307