Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 21000 found under Switch Optoelectronic by Ird Mechanalysis Inc. The National Stock Number assigned to this part is 5980013436160, and the Federal Supply Class is 5980 Optoelectrical Devices And Associated Hardware. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 21000.