Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5211B5017 found under Valve Regulating Fluid Pressure by Ross Operating Valve Co. The National Stock Number assigned to this part is 4820013711368, 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 5211B5017.