Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number X66MM found under Socket Socket Wrench by Stanley Black And Decker Inc. The National Stock Number assigned to this part is 5120013668584, 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 X66MM.