Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number VS2521-5F20 found under Bolt Shear by Alcoa Global Fasteners Inc. The National Stock Number assigned to this part is 5306009259773, and the Federal Supply Class is 5306 Bolts. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like VS2521-5F20.