This product features: able to lock the test data; 2 automatic shutdown; 3 wide measurement range: capable of measuring 1-9990ppm; 4 high accuracy: ± 2% error; 5 compact and lightweight: 15.5 × 3.1 × 2.3 (cm); unique temperature compensation function, can automatically be automatically converted into the TDS value under the 25 ° C water temperature; 7. waterproof design large-screen LCD for easy viewing durable; 8. extra long time without frequent replacement of the battery normal use for two years. Product description: win the cap of a pen, the ON switch; pen into the test solution, the solution shall have a height of more than 2 cm; stir the pen in solution until the reading is stable (10-30 seconds), the TDS value will be displayed in the To lock the screen, the value, press the HOLD button. The water after use, dry the tip of the pen, the pen cap cover can be back. Caution: avoid TDS pen to soak into the water, avoid direct sunlight and high temperature, Do not drop the weight and drop. ★ Product range: detection of pure water mineral water quality is in compliance with the standards for drinking water: pure water 50PPM the following: mineral water between 100 to 200 ppm. Laundry wash clean: to detect raw water or last use of water PPM data not too much. ★ testing tap water is qualified: the national standard of 50-300ppm. Pure alcohol: PPM value greater than 0, it means that impure. High value vegetables water PPM, chemical pollution, should attract attention.