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 5996-01-147-6054
NSN 5895-01-571-8577
NSN 5998-01-623-3701
NSN 5996-01-473-2024
NSN 5996-01-290-0499
NSN 5996-00-038-0234
NSN 5925-01-283-9588
NSN 5905-01-297-0836
NSN 6650-00-197-7563
NSN 5935-00-203-1292
NSN 5935-01-564-8953
NSN 5925-00-983-5666