The S4008LS3TP from Littelfuse is a Silicon Controlled Rectifier with Breakover Voltage 400 V, Breakover Current 8 A, Gate Trigger Voltage 1.6 V, Gate Trigger Current 0.0005 A, Temperature Operating Range -40 to 110 Degree C. Tags: Through Hole. More details for S4008LS3TP can be seen below.