Proximity sensor Response Frequency 35 Mhz With Box Type (18x18x36 pnp no)  are suitable for damp conditions and wide temperature range usage, unlike your traditional optical detection. A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. It often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal.

• It has a high reliability and long functional life