The STN4NF20L from STMicroelectronics is a MOSFET with Continous Drain Current 1 A, Drain Source Resistance 1100 to 1550 Milliohm, Drain Source Breakdown Voltage 200 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1 to 3 V. Tags: Surface Mount. More details for STN4NF20L can be seen below.