Proximity switches are the most common solution for non-contact detection. And the inductive type is the widely used proximity switches, which is through the electromagnetic waves to detect the metal abject near the sensor detection surface. In application, this is a very simple technology to detect 1”~2” metal object. Electric offer different series proximity sensor, that included inductive, photoelectrical, capacitive and etc.  Electric continues to improve the performance and quality, enabling the sensors in a world-class level . If you are searching for proximity switch,  will be your best choice.