The T173-4000 from Greegoo Electric is a Silicon Controlled Rectifier with Breakover Voltage 400 to 6500 V, Breakover Current 62000 A, Gate Trigger Voltage 2.5 V, Gate Trigger Current 250 mA, Temperature Operating Range -40 to 125 Degree C. Tags: Disc. More details for T173-4000 can be seen below.