METTLER TOLEDO has a wide range of in-line digital DO sensors, including
InPro 6850i digital amperometric dissolved oxygen sensors for sterile conditions
InPro 6860i digital optical DO sensors suitable for hygienic environments
InPro 6900i/6950i amperometric DO probes for brewing
InPro 6900i optical digital DO sensors for brewing
Digital UPW DO Sensors suitable for semiconductor water and power plant cycle chemistry.