The FMF300DXZ-34B from Mitsubishi Electric is a MOSFET with Continous Drain Current 300 A, Drain Source Resistance 4.9 to 7.16 milliohm, Drain Source Breakdown Voltage 1200 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1.8 to 3.2 V. Tags: Screw Mount. More details for FMF300DXZ-34B can be seen below.