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 6320-01-618-7800
NSN 5960-01-372-5609
NSN 5996-01-369-9209
NSN 6110-00-434-8237
NSN 5960-00-014-3445
NSN 6620-01-381-6225
NSN 6130-01-536-9671
NSN 5930-00-386-5963
NSN 6645-01-028-2186
NSN 5925-00-581-0393
NSN 5835-01-485-0210
NSN 5960-01-036-1223