This European Standard applies to breath alcohol test devices which measure the concentration of alcohol contained in an exhaled breath sample, designed and intended to be used as a self tester for the general public and to provide a reliable indication of the breath alcohol concentration at the time of the test. This European Standard specifies requirements for basic safety and performance, test methods and requirements for marking, labelling and operating instructions. This European Standard gives guidelines for compliance testing procedures consisting of a number of technical performance tests. It is not intended that the results of these devices should be used to rebut the results of evidential breath alcohol analysers covered by OIML R 126:1998, or breath alcohol test devices used in professional applications covered by EN 15964 or similar national regulations. Therefore, the results of measurements need to be displayed so as to protect, as far as it is practicable, the user from underestimating his alcohol concentration based on measurement uncertainties, intrinsic in every measurement.