As someone who just switched to a new MacBook Air, I now own several of Apple's MagSafe to MagSafe 2 Converters so all of my old power adaptors are still usable.

While the converters are cheap to replace at $10, they are tiny and thus, easy to lose.

The KeyBit Kickstarter project aims to make it harder to lose the little converter. This keychain is made from steel, and the converter just clips right in using the built-in magnet.

You can pick one up for just $15 if the project is funded.