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 5905-01-216-3824
NSN 5985-00-892-5884
NSN 5935-01-316-8093
NSN 6110-00-367-2427
NSN 6645-01-473-9179
NSN 5945-01-644-8447
NSN 5905-01-529-3041
NSN 5895-01-538-3451
NSN 5975-01-199-9382
NSN 5905-00-281-4111
NSN 6320-00-476-6898
NSN 6135-01-277-0599