The PROCAP I and II standard capacitance probes detect the presence or absence of material in contact with the probe by sensing minute changes (as low as 0.5 pF) in capacitance caused by the difference in the dielectric constant of the material versus the air. They feature interference-free operation, simple calibration, and fail-safe functionality and perform accurately even in dusty, sticky, or clinging materials. Class II hazardous location ratings and a wide assortment of probes and extensions make these point-level capacitance probes appropriate for a variety of solid, liquid, and slurry materials.