The YJS4447B from Yangjie Electronic Technology is a MOSFET with Continous Drain Current -18 A, Drain Source Resistance 5 to 10 milliohm, Drain Source Breakdown Voltage -30 V, Gate Source Voltage -25 to 25 V, Gate Source Threshold Voltage -2.8 to -1.2 V. Tags: Surface Mount. More details for YJS4447B can be seen below.