Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 391-8003NC found under Meter Frequency And Time Totaliz by Fei Zyfer Inc. The National Stock Number assigned to this part is 6695016165962, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 391-8003NC.