Field note: what this prox is and where it fits
This E2E-C06N04-CJ-C2 0.3M is an inductive proximity sensor from Omron's E2E family. Cylinder case, stainless steel body, unshielded. It's rated for a 4 mm sensing distance (0.157") and runs on 10-30 VDC, with an NPN normally-closed output on three wires. IP67 seals let it take the washdown and the oil mist out here on the lube route. Response frequency is 3 kHz, so it'll catch fast-moving targets without missing a count. LED indicator is built in for a quick visual check during setup.
What the ratings mean for your build
Sensing distance is 4 mm; unshielded means clearance from metal is required. NPN-NC output operates on 10-30 V supply.