Standalone ORP (oxidation-reduction potential) probes and electrodes for redox monitoring in water treatment, pool & spa, food processing and laboratory applications. Platinum-tipped, BNC-compatible replacement probes for Milwaukee ORP meters, plus GOnDO’s wide-range GO-51 electrode.
Need a complete handheld or benchtop ORP meter instead? See our ORP Meters range.
Standalone ORP (oxidation-reduction potential) probes and electrodes for redox monitoring in water treatment,...
Double junction ORP platinum electrode with 1 met…
Double junction, gel filled ORP electrode with pl…
ORP Electrode, Range: ±1500 mV
An ORP (oxidation-reduction potential) electrode measures the redox activity of a solution in millivolts — used to monitor disinfection strength in pool and spa water, chlorination effectiveness in water treatment, and sanitation levels in food processing and laboratory settings. Unlike a complete ORP meter, an electrode (or probe) is the sensing element alone — designed to connect to an existing meter or controller via a standard BNC connector.
Double junction electrodes (Milwaukee MA921B/2) isolate the reference cell behind two ceramic junctions instead of one, reducing the risk of clogging and contamination in dirty or high-solids samples — the better choice for pool, wastewater and industrial process water. Single junction designs are simpler and lower-cost, better suited to cleaner laboratory or drinking-water samples. Gel-filled electrolyte (used on both Milwaukee models here) removes the need to top up electrolyte levels; refillable designs offer longer service life with routine maintenance.
All three probes on this page use a standard BNC connector, compatible with Milwaukee ORP and pH/ORP combo meters that accept BNC inputs. The Milwaukee MA921B/2 is a direct replacement probe — sized and specified to restore a worn electrode without replacing the instrument.
Not sure which probe your meter takes? Contact us with your meter model.
Store the electrode tip in buffer or storage solution, never dry or in plain water. Clean regularly by soaking in a cleaning solution, and recalibrate against a known ORP standard (e.g. 200–275 mV, 600mV) on a routine schedule. See our ORP calibration solutions.
An ORP probe (or electrode) is the sensing element alone, connecting via BNC to an existing meter or controller. An ORP meter is the complete handheld or benchtop instrument with a display. If you need a full instrument, see our ORP Meters range; if you already own a meter and need a replacement or spare sensor, you're in the right place.
Any probe with a standard BNC connector will work with Milwaukee ORP and pH/ORP combo meters that accept BNC inputs. Contact us with your meter model if you're not sure.
Double junction electrodes resist clogging in dirty or high-solids water (pool, wastewater, industrial process) and are the safer default. Single junction suits cleaner lab or drinking-water samples.
Use a known ORP calibration/check solution (e.g. MA9020, ORP600) and follow the instrument's calibration procedure. Never store the tip dry — always in storage solution.
Typical service life is 12–24 months with routine cleaning and calibration, shorter in high-solids or high-temperature process water. A slow or drifting reading that won't calibrate is the clearest sign it's time to replace.
