Gastec 4HM Gas Detection Tubes - Hydrogen Sulphide High Mid-Range, 10 colorimetric tubes/box

Standard detector tubes are thin glass tubes with calibration scales printed from which you can directly read concentrations of the substances (gases and vapours) to be measured. Each tube contains detecting reagents that are especially sensitive to the target substance and quickly produces a distinct layer of colour change. The tubes are hermetically sealed. To assure a high precision, the tube's inner diameter is tightly controlled and detecting reagents with long term stability (many have a 3 year shelf life) are strictly selected.