The FDBL9403-F085T6 from onsemi is a MOSFET with Continous Drain Current 300 A, Drain Source Resistance 0.95 milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 4 V. Tags: Surface Mount. More details for FDBL9403-F085T6 can be seen below.