Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HH50 found under Gear Helical by Designatronics Incorporated. The National Stock Number assigned to this part is 3020009006799, 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 HH50.