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 2925-00-139-8309
NSN 6620-00-345-3456
NSN 5930-01-224-3655
NSN 5950-00-466-4215
NSN 6110-01-202-4837
NSN 6105-01-052-4040
NSN 6610-01-082-3531
NSN 4140-01-463-3295
NSN 5935-01-272-9592
NSN 6105-00-925-2226
NSN 5950-01-386-3075
NSN 5990-01-261-2962