The 270-WQ401 Dissolved Oxygen Sensor is a rugged reliable water oxygen level measuring device. The dissolved oxygen sensors are attached to 25' of marine grade cable, with lengths up to 500' available upon request. The dissolved oxygen sensor output is 4-20 mA with a three wire configuration. The dissolved oxygen sensor's electronics are completely encapsulated in marine grade epoxy within a stainless steel housing. The dissolved oxygen sensor uses a removable shield and dissolved oxygen element for easy maintenance.