The 2N4391 from Central Semiconductor is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 50 to 150 mA, Gate Source Voltage 40 V, Drain Source Resistance 30 Ohm, Gate Current 50 mA, Gate Reverse Current 0.1 nA. Tags: Through Hole. More details for 2N4391 can be seen below.