Contains the four basic tests for pool and spa water. Tests for Chlorine, pH, Acid Demand and Total Alkalinity. Clear-view acrylic test block features clearly embossed markings for chlorine range reading 0.4, 0.6, 1.0, 1.5, 3.0, and pH range reads 6.8, 7.2, 7.6, 7.8, 8.2.