The Omron E2B-M12KS02-WP-C1 5M is a shielded M12 inductive proximity sensor with a 2mm sensing distance, NPN normally open output, and a 5m PVC cable. It's rated for flush mounting so you don't lose detection range when embedded in metal.
What the ratings mean for fit
Shielded construction allows flush mounting in metal. NPN output is current-sinking; the normally open action means the output is off until a ferrous object enters the 2mm window. The M12 threaded barrel is short-body (shorter than standard), which helps in tight spaces. The 5m PVC cable gives you reach to the controller without a junction box. PVC is fine for dry, non-oily environments; if cutting fluid or coolant is present, consider a PUR cable variant.