Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number R4R03-535-11-B1 found under Valve Regulating Fluid Pressure by Hagglunds Drive Production Ab. The National Stock Number assigned to this part is 4820013745541, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like R4R03-535-11-B1.