Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MRS-120A-1S-1-4 found under by R K Electric Co Inc. The National Stock Number assigned to this part is 6645009078584, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like MRS-120A-1S-1-4.