Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 8ES 400 637-00 found under Transistor by Aero Electronics Systems Inc. The National Stock Number assigned to this part is 5961013610518, and the Federal Supply Class is 5961 Semiconductor Devices And Associated Hardware. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 8ES 400 637-00.