Omron Threaded Barrel Proximity Sensor, M8, 2 mm Detection, 12 → 24 V dc

Potted internal construction gives IP67 water washdown withstand capability
High visibility indicator
Pre-wired with 2m of cable
Shielded construction types allow for flush mounting

Stock numbers 319-4518 and 319-4473 are unshielded types

See typically (RS stock no. 7788757) for connectors compatible with the plug-in sensors