The STL18N65M5 from STMicroelectronics is a MOSFET with Continous Drain Current 15 A, Drain Source Resistance 215 to 240 Milliohm, Drain Source Breakdown Voltage 650 V, Gate Source Voltage - 25 to 25 V, Gate Source Threshold Voltage 3 to 5 V. Tags: Surface Mount. More details for STL18N65M5 can be seen below.