The Omron E2B-M30KS10-M1-B2 is a shielded 30mm cylindrical proximity switch — short body, brass housing, PNP output, normally closed. It picks up ferrous targets at 10mm, which is a common range for a 30mm shielded sensor. The shielded construction means you can flush-mount it in metal without worrying about false triggers from surrounding steel.
How it compares with the cable version
If you're looking at the E2B-M30KS15-WP-B2 2M — same housing, shielded, NC, PNP — the key differences are connection type and sensing distance. This M1-B2 has an M12 connector; the WP-B2 comes with a 2-meter pre-wired PVC cable. The WP-B2 also reaches 15mm instead of 10mm. They're not drop-in interchangeable: swapping from cable to connector means you'll need a mating M12 cordset and possibly re-termination at the panel. If your target range is 15mm, the WP-B2 is the one. For 10mm and an M12 harness, this M1-B2 is it.