Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number Y637 found under Oscillator Crystal Controlled by Greenray Industries Inc. The National Stock Number assigned to this part is 5955000633196, 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 Y637.