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 6610-00-540-8911
NSN 5945-00-011-8266
NSN 5960-01-245-3097
NSN 5915-01-130-2092
NSN 6220-01-315-6283
NSN 6685-01-247-0470
NSN 5925-00-233-5125
NSN 5920-01-416-8756
NSN 7035-01-438-2108
NSN 5835-01-024-9249
NSN 5998-01-552-0317
NSN 6220-01-457-5013