[Easy to use]: 5 seconds to know water quality, accurately and faster.This TDS PH combo kit.Besides, it offers the best price and reliable quality, making it your choice for testing water quality.[How accurate is it? The PH has a resolution of 0.01pH and an accuracy of ±0.01pH.TDS: 0~9990ppm, accuracy: ±2%.[Durable PH Pen] With automatic calibration function, no screwdriver is needed to calibrate the pH tester pen.The TDS pen has an automatic lock and shut-off function.[Portable] Small in size, it is suitable for testing the pH balance of drinking water, swimming pools, aquariums, reverse osmosis systems, spas or hydroponics.[Wide range of applications] Ideal for testing the pH of drinking water, plating solutions, boiler water, aquarium water, swimming pool water, photographic rinses,well water, deep water tables, aquaculture, food processing, etc.at home and in the laboratory.