A capo is a simple but essential tool that clamps across a guitar’s neck, raising the pitch by shortening the string length. Capos have been used for centuries, with early versions made from leather and metal. Modern capos provide better tension control and quick-release mechanisms. Leading brands include Kyser (Quick-Change Capo), Shubb (C1 Capo), G7th (Performance 3 ART Capo), and D’Addario (NS Tri-Action Capo). Used in folk, rock, and classical music, capos allow for easy key changes, open chord voicings, and creative tunings. Adjustable models suit different neck radii, while partial capos enable unique harmonic possibilities.