Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 421-010 found under Oscillator Noncryst by Datum Inc. The National Stock Number assigned to this part is 5955010643800, and the Federal Supply Class is 5955 Oscillators And Piezoelectric Crystals. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 421-010.