MS21206A, MILITARY STANDARD: WASHER, COUNTERSUNK AND PLAIN, FOR USE WITH BOLTS AND NUTS UP TO AND INCLUDING 220 KSI FTU (30 AUG 1991)
MS21206A, MILITARY STANDARD: WASHER, COUNTERSUNK AND PLAIN, FOR USE WITH BOLTS AND NUTS UP TO AND INCLUDING 220 KSI FTU (30 AUG 1991).