The 2N5551UBx from STMicroelectronics is a RF Transistor with Duty_Cycle 0.015, Gain 20 to 250 dB(DC Current Gain), Voltage - Collector Base (Vcbo) 180 V, Voltage - Collector Emitter (Vceo) 160 V, Voltage - Emitter Base 6 V. Tags: Surface Mount. More details for 2N5551UBx can be seen below.