The OP508FA from TT Electronics is a Phototransistor with Collector Emitter Voltage (Breakdown) 30 V, Collector-Dark Current 100 nA, Collector Emitter Voltage(Saturation) 0.4 V, Emitter Collector Voltage(Breakdown) 5 V, On-State Collector Current 2.7 mA. More details for OP508FA can be seen below.