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 6150-01-632-7285
NSN 5965-01-246-6162
NSN 6130-01-437-5576
NSN 5930-01-536-9639
NSN 6685-01-477-3890
NSN 5915-00-571-4748
NSN 5910-01-215-1374
NSN 5950-00-594-9172
NSN 6110-00-349-9331
NSN 5990-00-064-7229
NSN 6685-01-560-0574
NSN 5996-01-395-1909