The STYN1855 from Sirectifier Electronics is a Silicon Controlled Rectifier with Breakover Voltage 1800 V, Breakover Current 390 to 560 A, Gate Trigger Voltage 1.5 to 2.5 V, Gate Trigger Current 25 to 50 mA, Temperature Operating Range -40 to 125 Degree C. Tags: Through Hole. More details for STYN1855 can be seen below.