Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number M21 10400 00KC found under Crystal Unit Quartz by Vectron International Inc. The National Stock Number assigned to this part is 5955009139152, 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 M21 10400 00KC.