Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4N25S found under Coupler Optoelectronic by Fairchild Semiconductor Corp. The National Stock Number assigned to this part is 5980015159043, 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 4N25S.