The Panasonic EX-11B is an ultra-slim photoelectric sensor designed for through-beam applications. It offers a sensing distance of 15cm and an NPN open collector/dark-ON output.
The Omron E3S-2DE4 is a through-beam photoelectric sensor with a 2-meter sensing distance and NPN output. It operates on 12-24VDC and features a 3ms response time.