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 6685-00-453-0178
NSN 6620-00-251-0569
NSN 5985-01-062-0175
NSN 5950-01-476-0848
NSN 5915-01-081-7102
NSN 5999-00-833-9904
NSN 6620-00-004-5466
NSN 5915-01-342-1262
NSN 5960-01-614-8005
NSN 5975-00-583-8625
NSN 5950-01-465-5224
NSN 6145-01-516-9020