The Omron E2E-C04S12-WC-C1-R 5M is a shielded 4 mm diameter cylindrical proximity sensor from the E2E Small Diameter series. It switches at 1.2 mm with an NPN normally open 3-wire DC output. The pre-wired cable runs 5 meters and is bend-resistant, suited for tight routing in small machine cavities.
Fit notes
At 1.2 mm sensing distance, this is a tight-gap proximity switch. Shielded housing allows flush mounting in metal panels with no derating. The 4 mm smooth cylindrical barrel fits into small pilot holes or mounting blocks — typical for detecting small targets like pinions, pins, or thin ferrous tabs.
Not a swap with the E2C-X1R5AH
If you're hunting a second source, the Omron E2C-X1R5AH is another small shielded sensor but it's an M8 (8 mm) barrel with 1.5 mm sensing. The 4 mm vs 8 mm diameter means mounting holes and clearances are completely different. This E2E won't drop into a panel designed for an M8 without a bushing, and the 1.2 mm vs 1.5 mm gap changes target selection. Stick with the exact order code if your BOM specifies 4 mm.