Check the listing for details. (100 Pack) Analytical Test Indicator Strips to Detect Peroxide Up to 100 ppm New. Condition: New. Listed at 19.98 USD. Features: Container with 100 test strips Get easy readings at 0, 1, 3, 10, 50, and 100ppm The higher the peroxide level, the more blue the strip becomes No mechanical reader requiredProudly made in the US! ITEM DESCRIPTION Low Level Peroxide Test Strip up to 100ppm The Low Level Peroxide test strip detects residual peroxides, for example, in drinking water, pools, and hot tubs where Hydrogen peroxide was used as a disinfectant. This test strip is calibrated at 0, 1, 3, 10, 50, and 100ppm, and gives results in just seconds. Instructions: Remove one test strip from the vial. Do not touch the test pad with your fingers. Dip the test strip into the solution being tested for 1 second. Remove and shake off any excess liquid. Compare the test pad to the color chart after 10 seconds.