Brunette Girl Posing With The Guitar

A capo (short for capotasto) is used to change the pitch of open strings. Capos are clipped onto the fret board with the aid of spring tension, or in some models, elastic tension. To raise the guitar's pitch by one semitone, the player would clip the capo onto the fret board just below the first fret. Its use allows players to play in different keys without having to change the chord formations they use. Because of the ease with which they allow guitar players to change keys, they are sometimes referred to as "cheaters" or the "hillbilly crutch." Classical performers are known to use them to enable modern instruments to match the pitch of historical instruments such as the renaissance lute.
• Slides
A slide, (neck of a bottle, knife blade or round metal bar) used in blues and rock to create a glissando or 'Hawaiian' effect. The necks of bottles were often used in blues and country music. Modern slides are constructed of glass, plastic, ceramic, chrome, brass or steel, depending on the weight and tone desired. An instrument that is played exclusively in this manner, (using a metal bar) is called a steel guitar or pedal steel. Slide playing to this day is very popular in blues music and country music. Some slide players use a so called Dobro guitar.
Some performers that have become famous for playing slide are Robert Johnson, Elmore James, Ry Cooder, George Harrison, Bonnie Raitt, Derek Trucks, Warren Haynes, Duane Allman, Muddy Waters, Rory Gallagher, and George Thorogood.