Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 506978-12 found under Electron Tube by Aar Parts Trading Inc. The National Stock Number assigned to this part is 5960010252526, 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 506978-12.