[Convenient Use] 5 seconds to detect water quality, accuracy and faster. This combo game of TDS PH EC Temperature. Besides, it has the best price and reliable quality - all of which make it your first water quality tester. [How Accurate is it? ] The pH resolution is 0.01 pH, the accuracy is ±0.01 pH. TDS: 0-9990 ppm, Conductivity: 0-9990 us/cm, Accuracy: ±2%. It's the same as the great resolution brand on Amazon, but Pancellent test is only half the price. [Durable Model] PH pens have AUTO CALIBRATION function, no screwdriver type is required to calibrate the pH tester pen. The TDS pen has a lock & Automatic shutdown function. [Portable Bag] Small but suitable for testing the pH of drinking water, swimming pool, aquarium, reverse osmosis system, spa or hydroponics [Wide Application] Ideal for home and laboratory pH testing, including drinking water, electroplating liquid, boiler water, aquarium water, swimming pool water, photographic rinsing liquid, well water, deep phreatic water,