OPB700 and OPB700ALZ series of sensors from Optek consist of an infrared emitting diode and an NPN silicon phototransistor, mounted side-by-side on converging optical axes in a black plastic housing.
OPB701 and OPB701ALZ sensors consist of an infrared emitting diode and an NPN silicon photodarlington, and also mounted side-by-side on converging optical axes in a cost-effective black plastic housing.
The interconnect wires for these devices are UL approved #26 AWG, with Teflon insulation, stripped & tinned.
The OPB700 and OPB701 have 4" (101 mm) wire length while the OPB700ALZ & OPB701ALZ have 18" (457 mm) wire length.

Reflective Optical Sensors, Optek