The Low Range H2S Test has detection limits From 0 to 2ppm (mg/L) with a low sensitivity of 0.3ppm (mg/L). With this test, the strip is inserted into the aqueous sample for 20 seconds with back and forth motion. After 20 seconds, the strip is removed and discarded. The remaining discolored sample is compared to the color chart specific for this water quality test.Part # Numberof Tests Sensitivity Total Test Time 481197-20 30 packets of 1 0, 0.3, 0.5, 1.0, 2.0 ppm (mg/L) 1 Minute, 20Seconds