Probe for Bluelab Combo and pH Meter, as well as Bluelab Guardian Monitor. Bluelab pH Probe is a replacement with a pH probe (electrode) suitable for use with Bluelab products that test the pH of the solution. Unfortunately, the pH test is not eternal. With good care and use (maintenance of the probe and cleaning once a month) you will extend its durability. Bluelab pH Probe has a double bond that provides longer life and is finished with a disposable gel so that no additional maintenance is required, in addition to cleaning. Replace only the pH probe, not the whole tester! Bluelab gives a 6-month warranty
