Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 43916 found under Socket Socket Wrench by S K Hand Tool Corp. The National Stock Number assigned to this part is 5120000870697, and the Federal Supply Class is 5120 Hand Tools Nonedged Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 43916.