The OP560B from TT Electronics is a Phototransistor with Collector Emitter Voltage (Breakdown) 15 V, Collector-Dark Current 100 nA, Collector Emitter Voltage(Saturation) 1.10 V, Emitter Collector Voltage(Breakdown) 2 V, On-State Collector Current 3.3 to 9.8 mA. More details for OP560B can be seen below.