Key features - Indicator light for mineral water: the light turns on when the sample is mineral water, and remains off for non-mineral water. - Simple operation: gently immerse the pen tip in the water sample and observe the indication. Do not wet the main body of the pen. - Wide compatibility: suitable for testing water from energy water machines, functional water machines, ionized water machines, ultrafiltration water purifiers, RO water purifiers, and alkaline or mineralized energy cups to check whether the water is qualified. - High-precision copper probe: provides more accurate results with faster test speed. Applications - Home RO purifier: quickly verify the quality of water produced by a residential RO system. - Ionized or energy water machines: assess the output to ensure it meets expected mineralization or ionization levels. - Alkaline or mineralized energy cups: confirm the water sample is within acceptable quality before use. Notes - Do not wet the main body of the pen during use. - For best results, follow the simple immersion and observation procedure as described.