The STP40NF12 from STMicroelectronics is a MOSFET with Continous Drain Current 40 A, Drain Source Resistance 28 to 32 Milliohm, Drain Source Breakdown Voltage 120 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Through Hole. More details for STP40NF12 can be seen below.