Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SCD51990003-004 found under Delay Line by Harris Technical Services Corp. The National Stock Number assigned to this part is 5999012535783, and the Federal Supply Class is 5999 Miscellaneous Electrical And Electronic Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like SCD51990003-004.