The RM4503S (N) from Rectron Semiconductor is a MOSFET with Continous Drain Current -9.1 to 10 A, Drain Source Resistance 9 to 35 milliohm, Drain Source Breakdown Voltage -30 to 30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage -3 to 3 V. Tags: Surface Mount. More details for RM4503S (N) can be seen below.