The BSS138 from First Silicon is a MOSFET with Continous Drain Current 0.22 A, Drain Source Resistance 3.5 to 6 ohm, Drain Source Breakdown Voltage 50 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 0.8 to 1.5 V. Tags: Surface Mount. More details for BSS138 can be seen below.