The MDC325-18io3 from Littelfuse is a Silicon Controlled Rectifier with Breakover Voltage 1800 V, Breakover Current 345 A, Gate Trigger Voltage 0.75 V, Gate Trigger Current 785 A, Temperature Operating Range -40 to 125 Degree C. Tags: Surface Mount. More details for MDC325-18io3 can be seen below.