The RPM-20PB from ROHM Semiconductor is a Phototransistor with Collector Emitter Voltage (Breakdown) 32 V, Collector-Dark Current 0.5 uA, Collector Emitter Voltage(Saturation) 0.4 V, Emitter Collector Voltage(Breakdown) 5 V, Power Dissipation 100 mW. More details for RPM-20PB can be seen below.