Capos are used to change the key and pitch of a guitar sound without having to adjust the strings with the tuning keys. It should be noted that the capo is placed as close to the fret as possible.

A capo (short for capotasto, Italian for "head of fretboard", also called a fret lobster or cheater bar) is a device used for shortening the strings, and hence raising the pitch, of a stringed
instrument such as a guitar, mandolin or banjo. It was invented by the Flamenco guitarist Jose Patino Gonzalez.

There are several different styles of capo available, utilizing a range of mechanisms, but most use a rubber-covered bar to hold down the strings, fastened with a strip of elastic or nylon, a cam-operated metal clamp, or another device. Alternative terms are capo d'astro and capodastro, also Italian.