Breathalyzer technology measures blood alcohol concentration by analyzing exhaled air. After drinking, the alcohol evaporates into the lungs, and it's exhaled as vapor. Fuel-cell sensors with platinum electrodes react with ethanol in exhaled breath, producing electrons proportional to alcohol concentration. This current is converted to a BAC reading displayed digitally.

This employs a piston mechanism. As the pump head rises, it creates low pressure, drawing shampoo up like in a straw. When depressed, a ball blocks shampoo from returning.