Features:  Portable water tester pen adopts sensitive probe and can test TDS of the water. Easy, accurate, fast and steady to use.  Remove the protective cap and turn on the tester; immerse the electrode into water and stir gently; wait until the reading is stable and read the value; clean it with dry cloth.  Digital screen provides clear display, greatly enhancing reading experience. Battery operated, low power consumption, long service life.  This water quality analyzer can test the TDS of drinking water, tap water, water purifier, aquarium, swimming pool, hydroponics, aquiculture, agriculture, etc.  Compact and lightweight, comes with a small leather bag, easy and convenient portability.    Note:  1. TDS is one of the indexes of water quality; you can't just rely on it.  2. Size and color may be slightly different due to manual measurement and different light conditions. Thanks for understanding.    Specifications:  Color: Blue  Material: ABS  Screen: Digital Display  TDS Measuring Range: 0-9999ppm  Accuracy: ±2% (F.S)  Resolution: 1ppm  Function: TDS Testing, Data Hold  Built-in Battery: 2 * 1.5V LR44 Button Battery  Working Temperature: 0~50℃  Item Size: 142 * 25 * 15mm / 5.59 * 0.98 * 0.59in  Package Size: 15 * 3 * 3cm / 5.91 * 1.18 * 1.18in  Package Weight: 44g / 1.55oz    Package List:  1 * TDS Water Tester  1 * Small Leather Bag