The FQS4901 from onsemi is a MOSFET with Continous Drain Current 0.45 A, Drain Source Resistance 3200 to 4200 milliohm, Drain Source Breakdown Voltage 400 V, Gate Source Voltage -25 to 25 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Surface Mount. More details for FQS4901 can be seen below.