The 2N4858A from Central Semiconductor is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 8.0 to 80 mA, Drain Source Resistance 60 Ohm, Gate Current 50 mA, Gate Reverse Current 0.25 nA, Power Dissipation 0.36 W. Tags: Through Hole. More details for 2N4858A can be seen below.