The E3Z-D66 is a built-in amplifier photoelectric sensor using an IR light source for diffuse reflective detection, covering a sensing range of 5 to 100 mm and terminating through a connector. It draws 30 mA max, suited for short-range object presence in automated lines.
The E3Z-LT81 (through-beam, 60 m, red laser) and the E3S-CD12 (diffuse, 2 m, cable termination) are not direct functional replacements for the E3Z-D66. The E3Z-LT81 requires an emitter-receiver pair, while the E3S-CD12 uses a bulkier IP67 housing and prewired cable, so neither drops into a panel without rewiring or re-mounting.