The response time is set for a slight delay so that Panasonic SW-101 switch will not respond a falling object, such as a dropped tool. The switch is designed so that it will operate when touched by hand, but false operation will rarely occur when something is dropped onto it. Panasonic SW-111 saves the hassle of making an additional safeguard. In addition, with its ISO 13851 complying shape, even a knock on the elbow will not cause a false operation (light interruption). SW-111's detection does not operate when a hand is just placed onto the unit. With a design that only detects when fingers are bent in and lightly grip onto the unit, an intended startup is possible. Two sets of external input indicators (two colors) are provided, so that they can be used as operation indicators for a variety of purposes. If the light is continuously interrupted for more than 10 sec. by dust, etc., the switch is disabled and the fault indicator (yellow) illuminates. Because a Photo-MOS relay is used for the output, a single unit can be configured without a specific output polarity. In addition, there is no need for periodic replacement of parts such as contact-type relays.