Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 523-1 found under Circuit Card Assembly by Marc Alan Group The Inc. The National Stock Number assigned to this part is 5998004257948, 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 523-1.