The BUJ303B,127 from WeEN Semiconductors is a Bipolar Junction Transistor with Base Emitter Saturation Voltage 1 to 1.5 V, Emitter Cut off Current 0.1 mA, Collector Base Voltage 1050 V, Collector Cut off Current 0.1 to 2 mA, Collector Emitter Voltage 400 V. Tags: Through Hole, NPN Transistor. More details for BUJ303B,127 can be seen below.