The SSM6N55NU from Toshiba is a MOSFET with Continous Drain Current 4 A, Drain Source Resistance 33 to 64 Milliohm, Drain Source Breakdown Voltage 30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1.3 to 2.5 V. Tags: Surface Mount. More details for SSM6N55NU can be seen below.