Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BLK12 found under Key Set Socket Head Screw by Klein Tools Inc. The National Stock Number assigned to this part is 5120001167841, 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 BLK12.