Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number WD4000KS found under Disk Drive Unit by Western Digital Corp. The National Stock Number assigned to this part is 7025015409599, and the Federal Supply Class is 7025 Adp Input Output And Storage Devices. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like WD4000KS.