The STD12N50M2 from STMicroelectronics is a MOSFET with Continous Drain Current 10 A, Drain Source Resistance 325 to 380 Milliohm, Drain Source Breakdown Voltage 500 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Surface Mount. More details for STD12N50M2 can be seen below.