Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 172-0021 found under Microcircuit Digital by Autek Systems Corp. The National Stock Number assigned to this part is 5962010383455, and the Federal Supply Class is 5962 Microcircuits Electronic. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 172-0021.