[dual-backlit LCD screen] Engineered with dual-backlit LCD screen, our water hardness tester outperforms standard digital water testers, delivering superior nighttime visibility and effortless data reading. The intuitive color-coded system provides instant water safety feedback: Red backlight (40+ ppm) = Non-potable water warning; Green backlight (Less than 40 ppm) = Safe for direct drinking. [ Results] Our water quality tester features an advanced smart chip, stable measurements. Suitable for tap, filtered, aquarium, fish tank, swimming pool, well, and natural water sources, get accurate analysis every time. [Water Quality Tester] Seamlessly toggle between TDS, EC, and dual-scale temperature modes (℉/℃) with a single button. Quick-measure and data-hold functions deliver fast, reliable results - whether you're testing tap water , monitoring hydroponic nutrients, or checking pool chemistry outdoors. [ & Reliable Design] This water tester is built with high-quality ABS material, featuring a seamless shell and non-slip grips on both sides for comfortable handling. Inside, a dual-core processor ensures fast and accurate readings every time.