Sludge and soap residue build-up on the sides of RV black and gray water tanks can lead to false readings. The patented design of Horst Miracle Probes prevents false readings because they are considerably longer than standard probes and the sensor is surrounded by a Delrin body and teflon tube which prevents any liquid residue or sludge from setting up a conductive path. Easy to install as they fit the 3/8" diameter holes of existing probes Compatible with existing wiring and monitors, so they can simply be connected to the new