Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number EY81 found under Electron Tube by G E C Marconi Communications Ltd. The National Stock Number assigned to this part is 5960009671920, and the Federal Supply Class is 5960 Electron Tubes And Associated Hardware. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like EY81.