The TK1R4S04PB from Toshiba is a MOSFET with Continous Drain Current 120 A, Drain Source Resistance 1.1 to 1.9 milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 2 to 3 V. Tags: Surface Mount. More details for TK1R4S04PB can be seen below.