The RM40N40DF from Rectron Semiconductor is a MOSFET with Continous Drain Current 40 A, Drain Source Resistance 8.5 to 15 milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1 to 2 V. Tags: Surface Mount. More details for RM40N40DF can be seen below.