Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BT139-600 found under Semiconductor Device Thyristor by Advanced Semiconductor. The National Stock Number assigned to this part is 5961014210663, 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 BT139-600.