Precalibrated, maintenance-free tubes accurately and reproducibly indicate toxic gas concentrations. Box of 10 tubes. Gas detection tubes show color changes when a specific gas has been identified in the tested area. Make safety a priority for you and your workers by monitoring the workplace environment for hazardous gases. Research indicates fatalities in confined spaces can be prevented if confined space gas detectors or other early warning systems are present. Gas detection tubes are available for many gases including benzene, arsine, ethylene, vinyl chloride, hydrochloric acid, carbon monoxide, and more. Get clear, accurate results from hundreds of direct-read tubes. Sharp, clear color change for unambiguous measurements.