The Exner EXtract 840M is a manually operated retractable probe housing with ball valve made ​​of stainless steel for inline pH-measurement in pipes and vessels. Due to the very long, flexible adjustable immersion length the sensor can be very far inserted in the process. It provides the ability to separate the sensor under current process conditions from the process to carry out a cleaning or calibration or to take out the sensor along with the whole armature. The innovative design provides maximum safety for ease of use.