sentences:  This type of sensor is not extremely expensive and can be installed at pipeline pressure (in-situ).Water molecules do take time to enter and exit the pores, so some wet-up and dry down delays will be observed, especially after a slug.Contaminants and corrosives may damage and clog the pores causing a “drift” in the calibration, but the sensor heads can be refurbished or replaced and will perform better in very clean gas streams.