The YJS18N03A from Yangjie Electronic Technology is a MOSFET with Continous Drain Current 18 A, Drain Source Resistance 4.5 to 10 milliohm, Drain Source Breakdown Voltage 30 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 1 to 2.5 V. Tags: Surface Mount. More details for YJS18N03A can be seen below.