Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4N-4387 found under Gearspur by Carter Machinery Co. The National Stock Number assigned to this part is 3020016926019, 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 4N-4387.