Since 1953 used method for preliminary detection of an alcohol influence (Producer: Dräger Sicherheitstechnik GmbH, Germany). The tubes are filled with the yellow colored potassium salt of chromic acid which changes by reaction with the alcohol in the breath to the green colored chrome(III), whereby the length of the green zone is proportional to the breath alcohol content.
Hand-held breath-alcohol measuring instrument from Dräger Sicherheitstechnik GmbH, based on electochemical measurement with digital read-out. This breathalyser replaces the alcotest tubes since about 1995 in preliminary breath-alcohol testing.
"The Alcotest 7110 fulfills, with its different options, worldwide the most stringent requirements for measuring breath alcohol concentration. It is always used when especially high precision is needed. Therefore, measurements of breath alcohol concentration with the Alcotest 7110 are in many countries approved in courts and its authenticity is put on a par with blood analysis" (citation: Dräger). This breathalser is available in many different models, p.e. with infrared sensor, a combination of infrared and electochemical sensors, and together with additional measurement of the breath temperature. The last model fulfills the strict requirements of the german legislation.