The STD12N65M2 from STMicroelectronics is a MOSFET with Continous Drain Current 8 A, Drain Source Resistance 420 to 500 Milliohm, Drain Source Breakdown Voltage 650 V, Gate Source Voltage - 25 to 25 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Surface Mount. More details for STD12N65M2 can be seen below.