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 6610-01-009-3263
NSN 5996-01-047-0087
NSN 5920-01-586-5810
NSN 6610-01-565-9857
NSN 6620-01-170-8270
NSN 6645-01-627-8040
NSN 6130-01-054-4498
NSN 5930-01-653-6161
NSN 6130-01-525-3169
NSN 5960-01-488-5817
NSN 5985-00-867-0717
NSN 6620-00-984-7252