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 7035-01-332-2304
NSN 6150-01-629-2137
NSN 5960-00-269-3023
NSN 5998-00-435-0885
NSN 5915-00-062-6127
NSN 5990-01-251-7313
NSN 2925-00-221-8529
NSN 5905-01-632-0267
NSN 5985-01-139-4667
NSN 6650-00-754-2276
NSN 6220-01-592-3183
NSN 2925-00-253-1655