Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 40421800020(500 found under Diaphragm Assembly by Kollsman Inc. The National Stock Number assigned to this part is 6610000076832, and the Federal Supply Class is 6610 Flight Instruments. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 40421800020(500.