Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CR53AU found under Crystal Unit Quartz by Electronic Research Co. The National Stock Number assigned to this part is 5955000676766, 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 CR53AU.