Purpose: suitable for drinking water, aquariums, swimming pools, spas, sewage, and other liquids. It can also be used to test the water in the hot tub and it will work normally. Easy to use: it is also very simple for users who use it for the first time, just soak a piece of test paper in water for about 2 seconds, take it out and lay it flat, and compare it with the color chart after 15 minutes. Upgrade 6-in-1: the test strip has been upgraded with a 6-in-1 function, which can test six kinds of PH values, total chlorine, free chlorine, total alkalinity, cyanuric acid, and total hardness at the same time. More effective than other test strips. Quality: 100 swimming pool test strips are made of high-quality imported filter paper. Each hot tub test strip has 6 color indications, with high real-time accuracy and high reliability. Easy to store: the test paper is packed in a container that is easy to store to ensure long-term preservation. Material: PH test paper Size: 230 mm (Due to the manual measurement, there will be an error of 1-3 cm.) Measurement accuracy: 0.5 Measuring range: 0-1000 Each test strip can be tested at the same time