The STD9NM40N from STMicroelectronics is a MOSFET with Continous Drain Current 5.6 A, Drain Source Resistance 730 to 900 Milliohm, Drain Source Breakdown Voltage 400 V, Gate Source Voltage - 25 to 25 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Surface Mount. More details for STD9NM40N can be seen below.