Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CA21189-4-10HS found under Screw Cap Socket He by Alcoa Global Fasteners Inc. The National Stock Number assigned to this part is 5305012866044, and the Federal Supply Class is 5305 Screws. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like CA21189-4-10HS.