Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CA4520-4-18 found under Screw Close Tolerance by Alcoa Global Fasteners Inc. The National Stock Number assigned to this part is 5305001218895, 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 CA4520-4-18.