Features: 1.It can meet all your needs. Application for drinking water, aquarium, swimming pool and spa, industrial water, pond, bathtub water, agricultural water. 2.Water test strips are used to be sure of its safety. testing your water once per year is recommended by the EPA. 3.Easy to use. Simply dip one test strip into the water and wait for 5 seconds. Remove the testing strip, hold it horizontally for 30 seconds, and then compare it to the total Alkalinity, pH, Iron, Copper, Lead, Total Hardness, and Free Chlorine against the color on the chart to get a rought estimate. 4.Detects chemicals that are colorless and odorless. 5.Comes in easy-to-store container. Specifications: Quantity: 50/100 Pieces(for choice) Accuracy: 96% Quality guarantee period: 1 year Material: PET Test time: 30 s Advantage: not interfered by VC Notice: After opening, the cover should be sealed and stored in a dry place at 2 ~ 30 away from light. Please use it up as soon as possible. includes: Choice 1: 50 x Water Test Strips Choice 2: 100 x Water Test Strips