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 6645-00-968-6118
NSN 5930-01-620-5334
NSN 6240-01-503-5404
NSN 5910-01-492-5124
NSN 6620-01-026-7371
NSN 6150-01-394-3308
NSN 6110-00-019-7576
NSN 5855-00-797-8217
NSN 4140-00-643-3744
NSN 5905-00-982-5542
NSN 6150-01-415-3573
NSN 6135-01-384-7155