The STD2NK90ZT4 from STMicroelectronics is a MOSFET with Continous Drain Current 2.1 A, Drain Source Resistance 5000 to 6500 Milliohm, Drain Source Breakdown Voltage 900 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 3 to 4.5 V. Tags: Surface Mount. More details for STD2NK90ZT4 can be seen below.