The TPWR8503NL from Toshiba is a MOSFET with Continous Drain Current 300 A, Drain Source Resistance 0.72 to 1.3 milliohm, Drain Source Breakdown Voltage 30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1.3 to 2.3 V. Tags: Surface Mount. More details for TPWR8503NL can be seen below.