The RF4L040AT from ROHM Semiconductor is a MOSFET with Continous Drain Current 4 A, Drain Source Resistance 70 to 100 milliohm, Drain Source Breakdown Voltage -60 V, Gate Source Voltage 20 V, Gate Source Threshold Voltage -2.5 to -1 V. Tags: Surface Mount. More details for RF4L040AT can be seen below.