1.Preferred material: made of PVE and other materials, safe and environmentally friendly, no pollution. 2. The family pool test zone for pools and spas. Test 6 parameters: nitrate, nitrite, ph, residual chlorine, total hardness, total alkali. 3. Extremely easy-to-use swimming pool water quality test strip, using simple and clear instructions to get reliable results immediately. Just dip it and compare it with the big color chart on the bottle. for Ideal marked on the bottle. 4.50 averages and 50 tests-each swimming pool test strip can provide accurate and fast results for any water source (including for fresh and salt water swimming pools, spas and hot tubs). 5.6-in-1 swimming pool aquarium test strips bring you a different experience.