The MS T122S09UB from MS Power is a Silicon Controlled Rectifier with Breakover Voltage 900 V, Breakover Current 2200 to 3000 A, Gate Trigger Voltage 3.0 V, Gate Trigger Current 150 mA, Temperature Operating Range -40 to 125 Degree C. Tags: Stud Mount. More details for MS T122S09UB can be seen below.