DrägerTubes® are glass vials filled with a chemical reagent that reacts to a specific chemical or family of chemicals. A calibrated 100mL sample of air is drawn through the tube with the Dräger accuro® bellows pump. If the targeted chemical(s) is present the reagent in the tube changes color and the length of the color change typically indicates the measured concentration. The DrägerTubes® System is the world’s most popular form of gas detection.