The BSS138DWK from Diodes Incorporated is a MOSFET with Continous Drain Current 0.31 A, Drain Source Resistance 1200 to 5200 milliohm, Drain Source Breakdown Voltage 50 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage 0.5 to 1.5 V. Tags: Surface Mount. More details for BSS138DWK can be seen below.