The B2M040120R from BASiC Semiconductor is a MOSFET with Continous Drain Current 41 to 58 A, Drain Source Resistance 40 to 70 milli-ohm, Drain Source Breakdown Voltage 1200 V, Gate Source Voltage -8 to 22 V, Gate Source Threshold Voltage 1.9 to 3.5 V. Tags: Surface Mount. More details for B2M040120R can be seen below.