The PROCAP IX and IIX capacitance sensors feature CSA Class I, Groups C & D and Class II, Groups E, F, & G ratings. Suitable for challenging environments where there is a risk of explosion, they detect high or low levels in vessels used for volatile material storage. They function by detecting 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. A vast assortment of probes and extensions make these point-level capacitance probes highly customizable for a variety of solid, liquid, and slurry materials.