Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 277 0553 020 found under Oscillator Crystal by Rockwell Collins Inc. The National Stock Number assigned to this part is 5955013946585, 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 277 0553 020.