This E2E-X20MD2-M1G is a current-production inductive proximity switch from Omron's E2E NEXT line. 20 mm sensing distance, unshielded, so it sees metal targets from the side as well as the face. Output is DC 2-wire, normally closed, with an M12 connector per IEC arrangement. That's the quick answer for a sourcing buyer: it's active, it's spec'd, and it's ready to order.
The E2KQ-X10ME1 gets brought up as a second-source, but that's a capacitive sensor with a different game: 10 mm range, NPN-NO 3-wire output, cable leads. The E2E-X20MD2-M1G is inductive, 2-wire, and normally closed. Dropping one in for the other means rewiring and rethinking the logic — not a panel-swap. Stick with the inductive DC 2-wire family if you need a direct drop-in.