The RM40N40D3 from Rectron Semiconductor is a MOSFET with Continous Drain Current 40 A, Drain Source Resistance 5.7 to 14 milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1 to 2.5 V. Tags: Surface Mount. More details for RM40N40D3 can be seen below.