The MCR3818-8HR from Digitron Semiconductors is a Silicon Controlled Rectifier with Breakover Voltage 600 V, Breakover Current 240 A, Gate Trigger Voltage 0.2 to 2.5 V, Gate Trigger Current 40 to 75 mA, Temperature Operating Range -40 to 125 Degree C. Tags: Stud Mount. More details for MCR3818-8HR can be seen below.