Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number TSTD-1821 found under Relay Electromagnet by Precision Switching Inc. The National Stock Number assigned to this part is 5945011603911, 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 TSTD-1821.