Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B3A42 found under Gear Spur by Brunson Instrument Company Inc. The National Stock Number assigned to this part is 3020010211788, 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 B3A42.