Omron E3T-ST11 is a through-beam photoelectric sensor set with 1 m sensing range, 1 msec response, and IP67 sealing. It outputs NPN light-on and detects a 2 mm opaque object via prewired cable with bare wire termination.
How it compares to the rest of the E3T family
The closest peer is E3T-ST12 – same form factor, same NPN output, same 1 m range, but E3T-ST12 switches dark-on. That means swapping between ST11 and ST12 isn't mechanical drop-in if your PLC logic expects light-on. If you need PNP output instead, look at E3T-ST14 (PNP, dark-on). A different sibling, E3T-FT11, uses a smaller rectangular body (4 mm depth vs 10 mm) and halves the sensing range to 500 mm – not a direct dimensional swap.