Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number A2.1680 ITEM 18 found under Pulley Groove by Marine Equipment Inc. The National Stock Number assigned to this part is 3020013908117, and the Federal Supply Class is 3020 Gear Pulley Sprocket And Transmission Chain. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like A2.1680 ITEM 18.