Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 2500-99-1 found under Membrane Unit Coupl by John Crane Inc. The National Stock Number assigned to this part is 3020002289050, 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 2500-99-1.