Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CD521 found under Disk Asy W Facing by Borgwarner Corp. The National Stock Number assigned to this part is 2520007348385, and the Federal Supply Class is 2520 Vehicular Power Transmission Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like CD521.