Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 42312D42 found under Retainer Piston by B And R Machine And Tool Corp. The National Stock Number assigned to this part is 4320012438849, 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 42312D42.