From Shubb: "When the Shubb capo was first introduced about 40 years ago, guitarists throughout the world fell in love with it. They’re still in love with it today. We’ve given it a few tweaks through the years, but its basic mechanical principle remains the same: a unique over-center locking mechanism that provides an unrivaled combination of power, speed, accuracy and ease of use. One smooth flip of the lever locks it securely in place, and removes it just as quickly. And the Shubb capo is BY FAR the best at not creating tuning problems. Its soft, resilient rubber is specially designed to work just like a fingertip, so it doesn’t bend the strings over the frets. Its closing action is just like your hand, so it doesn’t pull the string off center. As a result, no re-tuning is necessary!
Our model 3 capos — “for 12-String Guitar” — are 2.25″ wide and curved. Not strictly for 12-strings, they fit any steel string guitars with wide fretboards."