"GALLIUM ARSENIDE LIGHT SOURCE DIODE OPTICALLY COUPLED TO A SILICON NPN PHOTOTRANSISTOR,PORM 1 KV INPUT TO OUTPUT VOLTAGE,4 WIRE LEAD TYPE TERMINALS,METAL CASE,0.220 IN. DIA BY 0.206 IN. LG,@HERMETICALLY SEALED,MINUS 55 DEG C TO PLUS 125 DEG C OPERATING TEMP RANGE"