What's A Breathalyzer

"Shhaaayyy, buddy, what's a 'Breathalyzer'?" asked one drunk to his friend at the next barstool.

"Well, I'd have to say it's a bag that tells you when you've drunk way too much," answered the equally wasted gent.

"Ah hell, whaddya know? I've been married to one of those for years and years now!"