Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 31B1242ISSUEA found under Shield Electron Tube by I T I Electronics Inc. The National Stock Number assigned to this part is 5960002846127, 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 31B1242ISSUEA.