Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number RV-40 42A USED ON S N 55901-4 found under Pump Reciprocating by The Walter Machine Co Inc. The National Stock Number assigned to this part is 4320013482580, and the Federal Supply Class is 4320 Power And Hand Pumps. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like RV-40 42A USED ON S N 55901-4.