The CRF2 comes with either a rigid or flexible probe depending on application installation need and probe length required. Featured in the CRF2 is easy push button calibration of zero and span. Custom order the CRF2 to any length probe that you need for your application. FEP covered probe is ideal for use with corrosive media. This technology also provides immunity to external RF sources like walkie-talkies and cell phones as well as minimal interference with radio communication or other electronic systems.