Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 31B2028 X012 found under Plate Diaphragm Act by Fisher Controls Co Inc. The National Stock Number assigned to this part is 4820013851700, 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 31B2028 X012.