The Si1021R from Vishay is a MOSFET with Continous Drain Current 0.17 A, Drain Source Resistance 4000 to 8000 milliohm, Drain Source Breakdown Voltage -60 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage -1 to -3 V. Tags: Surface Mount. More details for Si1021R can be seen below.