Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 500-821600 found under Module Ion Input by Siemens Building Technologies Inc. The National Stock Number assigned to this part is 4210011240657, and the Federal Supply Class is 4210 Firefighting Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 500-821600.