Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 531-021 found under Relay Electromagnet by American Metals Company. The National Stock Number assigned to this part is 5945013954261, and the Federal Supply Class is 5945 Relays And Solenoids. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 531-021.