These test strips are designed to test iron at very low levels in water: Simple Dip-Wait-Read Testing Method Test strips are stored in a foil pouch to protect them Ideal for quick and reliable testing of water Accurate results are achieved in less than 3 minutes This product is safe and easy to use since there are no chemicals to mix, an MSDS is not required These Iron Test Strips are safe and easy to use for fast accurate results within the ranges of 0 to 5 ppm (mg/l), which permits the measurement of typical iron levels found in well, tap and stream water.