used to measure the pH / cl2 (chlorine) of the solution and water. easy to use, no need for chemicals, practice to transport. level of chlorine recommended for swimming pool and spa : 2 to 1.7 ppm and 7.2 to 7.8 pH for PH level for pool and spa. Use in spas, swimming pools, river water, soil -free cultivation, aquariums, hydroponics and other systems of water. Content: 1 pH and CL2 tester (battery not included), 1 manual (French not guaranteed).