Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number XCS-4M3 found under Switch Push by Killark Electric Mfg Co. The National Stock Number assigned to this part is 5930012099548, 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 XCS-4M3.