Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BB-1-55-50 found under Belt Flat by Fournier Rubber And Supply Co. The National Stock Number assigned to this part is 3030004317880, and the Federal Supply Class is 3030 Belting Drive Belts Fan Belts And Accessories. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like BB-1-55-50.