The BSS138 from Taiwan Semiconductor is a MOSFET with Continous Drain Current 0.26 A, Drain Source Resistance 1100 to 3000 milliohm, Drain Source Breakdown Voltage 50 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 0.8 to 1.6 V. Tags: Surface Mount. More details for BSS138 can be seen below.