A Breathalyzer is an ingenious electronic device that measures a person’s blood alcohol content(BAC) from a simple breath sample. Regardless of the type, each design features a mouthpiece, a tube through which air is blown, and a sample chamber where the air is collected. The sample chamber consists of two vials, each one containing a unique chemical reaction mixture. The results will be determined by how your breath sample reacts with each of the two chemical compositions.\r