Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number XX221X16-18S4S found under by National Magnetic Sensors Inc. The National Stock Number assigned to this part is 5930014203045, and the Federal Supply Class is 5930 Switches. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like XX221X16-18S4S.