The STW40NF20 from STMicroelectronics is a MOSFET with Continous Drain Current 40 A, Drain Source Resistance 38 to 45 Milliohm, Drain Source Breakdown Voltage 200 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Through Hole. More details for STW40NF20 can be seen below.