PR12-4DN is a cylindrical Proximity Sensor that makes maintenance and wiring works easier than ever. Also, it realizes world-best class superior noise resistance characteristics with dedicated IC. Improved noise resistance with dedicated IC Built-in reverse polarity protection circuit (DC 3-wire type) Built-in surge protection circuit Built-in overcurrent protection circuit (DC type) Protection structure IP67 (IEC standard) for connector part Replaceable for micro switches and limit switches "