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 5996-01-086-3395
NSN 5910-01-279-9694
NSN 5905-01-196-0829
NSN 5895-01-524-4549
NSN 5925-00-525-4037
NSN 5950-01-474-6085
NSN 5945-01-075-3229
NSN 6110-01-209-9964
NSN 5930-00-636-2440
NSN 6105-01-475-0299
NSN 6145-01-519-8210
NSN 2925-01-274-8576