The E2EX3B1T8M5OMS: Termination is an M8 3-pin connector — the same footprint used across many Omron M8 proximity sensors. The body is 13 mm wide and 37.8 mm long, so it fits standard M8 mounting holes and brackets.
The E2EX9B1T12M1OMS is a flush-mount M12 sensor with 9 mm sensing distance. The E2EX3B1T8M5OMS is quasi-flush, shorter range, and uses an M8 body and connector. If your panel was drilled for an M12 port, this unit won't drop in without an adapter — the mounting threads and connector are different sizes. But for tight spaces where only 3 mm of detection is needed and wash-down protection matters, the M8 form factor saves panel real estate.
Quasi-flush mounting means the sensing face can be recessed up to the face of a metal bracket without derating the 3 mm range — useful for slide-gate or die-close detection where the sensor must sit recessed. Connect the M8 3-pin to a standard M8 cable assembly; PNP NO output pulls high on detection. Supply must stay within 10–30 VDC; reverse polarity protection is built in.