Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 500666 found under Frame Beam by Clamshell Structures Inc. The National Stock Number assigned to this part is 5450013280170, and the Federal Supply Class is 5450 Miscellaneous Prefabricated Structures. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 500666.