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 6105-00-925-2226
NSN 5935-01-202-5008
NSN 6145-01-525-8140
NSN 6320-00-682-3448
NSN 6610-01-058-2366
NSN 5985-00-235-2048
NSN 6320-01-098-2503
NSN 6645-01-423-9361
NSN 5835-01-485-0210
NSN 7035-00-140-3070
NSN 2925-00-924-5040
NSN 5910-00-936-8103