The 66189-103 from Micropac Industries is a Space Qualified Optocoupler with Forward Voltage 2 to 2.2 V, Isolation Voltage 500 V, On-State Collector Current 2 to 3 mA, Power Consumption 230 mW(Power Dissipation), Resistance 10 Ohms. Tags: Through Hole. More details for 66189-103 can be seen below.