The YJS4409A 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 -25 to 25 V, Gate Source Threshold Voltage -2.5 to -1 V. Tags: Surface Mount. More details for YJS4409A can be seen below.