BreathKey Breathalyzer: The Digital Keychain Breath Alcohol Tester with Professional Features  Product Description: BreathKey is the smallest and lightest breathalyzer in the world, but it is big on features and quality. Unlike other bulky breathalyzers, it easily fits on a keychain so you can take it with you wherever you go. And it is the only consumer breathalyzer at any size or price that has a fuel cell alcohol sensor, the same type that is used in police equipment. The BreathKey breath alcohol tester is FDA certified, and has a lifetime battery that is good for many years of daily use. It also has an advanced backlit display with simple plain English prompts. One button operation gives results in seconds.