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 6150-00-559-8369
NSN 5990-01-421-5342
NSN 5835-01-656-0261
NSN 5945-00-128-2972
NSN 6650-01-072-4986
NSN 6645-01-466-9477
NSN 5855-00-631-4565
NSN 5835-00-334-6556
NSN 6685-01-634-0611
NSN 6105-01-028-3330
NSN 5915-01-100-2511
NSN 6145-00-421-6874