The FMF400BX-24B from Mitsubishi Electric is a MOSFET with Continous Drain Current 400 A, Drain Source Resistance 3.4 to 4.8 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 FMF400BX-24B can be seen below.