Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number WK-5550 U03 found under Printed Circuit Board by Sanrex Corp. The National Stock Number assigned to this part is 5998016758098, and the Federal Supply Class is 5998 Electrical And Electronic Assemblies Boards Cards And Associated Hardware. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like WK-5550 U03.