Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number L221910-127 found under Crystal Unit Quartz by Raytheon Company. The National Stock Number assigned to this part is 5955009426660, 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 L221910-127.