OxyGuard Model 420 2-wire 4-20 mA probe-transmitter with galvanic isolation. Loop supply: 12-33VDC , 5m cable as standard,  accessory kit included. For pure oxygen or DO levels above 40 ppm; or for high oxygen levels as found in aquaculture and the environment; or for low oxygen levels as found in waste water treatment, inert gas etc..

NB. Each of the above Model 420 variants can be ordered to measure volume percent oxygen, ppm (mg/l) dissolved oxygen or % saturation dissolved oxygen. They can also be ordered with mineral oil proof membrane, or with an adaptor for mounting onto a blind flange.