Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5657 found under Electron Tube by Philips Electronics Nederland Bv. The National Stock Number assigned to this part is 5960001667693, 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 5657.