MA9016 is a lab grade electrode cleaning solution prepared with premium chemicals to improve the performance & extend the life of your pH & ORP electrodes, testers & pens. Your accuracy & speed of your results are dependent on your pH sensing bulb & ORP platinum tip being clean. pH & ORP electrodes also need a free flowing junction to function. Milwaukee's cleaning solution helps both keep sensing parts clean & the junction open. Simply open the bottle, fill a beaker or container so that the level covers the sensor and junction, & soak for 15 to 20 mins.