Here's a 'Key' bottle opener that attaches to your key ring. It doesn't take up any more space than a normal key. Convenient, small profile, Awesome!
Back in the day, everybody had a cheap bottle opener. It was brightly coloured and probably had a sports team logo or other loud design on it. When beer appeared, you and your buddies simultaneously whipped out your keychains and were able to peel back your bottle caps with ease. That is, until your opener snapped or bent.