The 81RK120 from RIR Power Electronics is a Silicon Controlled Rectifier with Breakover Voltage 1200 V, Breakover Current 1730 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 81RK120 can be seen below.