Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5631 1-2 found under Lock Set Mortise by Eastern Controls Inc. The National Stock Number assigned to this part is 5340000338873, and the Federal Supply Class is 5340 Hardware Commercial. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 5631 1-2.