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 6240-01-479-9964
NSN 6320-01-125-3361
NSN 5835-01-143-9143
NSN 5960-01-487-6436
NSN 5996-00-186-6186
NSN 6110-01-585-1017
NSN 5985-01-339-3430
NSN 5985-01-291-7131
NSN 6650-01-628-3745
NSN 5835-00-198-4936
NSN 5920-01-387-0819
NSN 5895-01-565-2414