The J304 from New Jersey Semiconductor is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 5 to 15 mA, Gate Source Voltage 30 V, Forward Transfer Admittance 14.2 to 180 mS, Continous Drain Current 1 nA, Drain Source Breakdown Voltage 15 V. Tags: Through Hole. More details for J304 can be seen below.