The BreathKey Model g10 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. It has an advanced backlit display with simple plain English prompts. One button operation gives results in seconds. And it is the only key chain breathalyzer that has a fuel cell alcohol sensor, the same type that is used in police equipment. Its accuracy and performance have been certified by the FDA.