Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 21900-39 found under Valve Aircraft Mate by Parker Hannifin Ltd. The National Stock Number assigned to this part is 1680015241537, and the Federal Supply Class is 1680 Miscellaneous Aircraft Accessories And Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 21900-39.