Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B77T0257 0121 found under Microcircuit Digita by Mcdonnell Douglas. The National Stock Number assigned to this part is 5962010180555, 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 B77T0257 0121.