Also known as inductive proximity switches, these detect metallic objects even if they’re obscured by water, oil, dirt, or a surface finish.

High-frequency sound waves detect objects of all shapes and sizes—even when obscured by smoke, dust, or chips.

Verify the signal output type of DC switches—a red light indicates NPN, and a green light indicates PNP.

This switch mounts to the outside of your tank and detects chemical level through plastic tank walls by measuring the capacitance between the switch and tank contents; it cannot be used with metal tanks.