ifm electronic Capacitive switch, IP69

Actuated by sensors using patented Field Effect Technology which converts the touch of the operators hand into an electrical output. The two sensors have to be touched within 0.2 seconds of each other and can differentiate between a person's hand and most solid objects/substances, as well as resistance to accidental actuation via clothing, fluid, splashes etc.,There are built in diagnostic safeguards for power-up protection, foreign object intervention and film/deposit interference which all result in LED indication.