1. The electrode uses electrical space.Please clean the electrode with distilled water and put it in a protective bottle.It will be activated by injecting the solution before the next test.2.If the electrode is not used for a long time, it should be rinsed and the remaining distilled water should be absorbed.3. The sensitive glass bulb on the front of the electrode should not be in contact with hard objects, any damage and scratches will make the electrode invalid.4. After long-term use of the electrode, the slope and response speed of the electrode may decrease. The measuring end of the electrode can be immersed in 4% HF for 3-5 seconds or indiluted HCL solution for 1-2 minutes, then cleaned with distilled water in chlorine Soak in potassium solution (4M) to rejuvenate5. If there is a substance in the tested container that is easy to contaminate the sensitive bubble or block the liquid junction to passivate the electrode, the response speed will be significantly slower, the slope will be reduced or the reading will beunstable, so you must choose according to the nature of the pollutant. Clean with a suitable solution to renew it. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin