Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B20-04537 found under Cap End Actuator by Portland Valve Llc. The National Stock Number assigned to this part is 3010011998036, and the Federal Supply Class is 3010 Torque Converters And Speed Changers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like B20-04537.