The STD11N50M2 from STMicroelectronics is a MOSFET with Continous Drain Current 8 A, Drain Source Resistance 450 to 530 Milliohm, Drain Source Breakdown Voltage 500 V, Gate Source Voltage - 25 to 25 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Surface Mount. More details for STD11N50M2 can be seen below.