These strips are perfect for testing the available chlorine in bleach solutions-great for Conformance to CDC surface disinfection recommendations. Check available chlorine at 0, 1000, 2500, 5000, 7500, and 10,000 ppm. Each Test takes approximately 30 seconds. Packaged in a vial of 50 strips. Each vial is lined with desiccant to maintain freshness. Broad-range Test strips handle high-level available chlorine testing up to 10,000 ppm