Part number 391.21 appears under 4 stock numbers

Manufacturers reuse part numbers across items. Each stock number below is its own federal item record — pick the one your drawing or solicitation cites.

5120-01-617-6235 — SOCKET,SOCKET WRENCH · FSC 5120
6515-01-243-0536 — TIGHTENER,WIRE,BONE FIXATION · FSC 6515
8940-01-259-9357 — MILK SUBSTITUTE · FSC 8940
5935-01-501-4192 — ADAPTER,CONNECTOR · FSC 5935