Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MCM677B-4.474MHZ found under Oscillator Crystal by Q Tech Corp. The National Stock Number assigned to this part is 5955011537635, 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 MCM677B-4.474MHZ.