The world's first dedicated guitar loudspeaker is a significant part of musical history. In the 1950s, Celestion recognized the emergence of a new breed of musician—the electric guitarist—and to their need for a rugged, reliable loudspeaker by modifying G12 radio. The unique character of the Celestion Blue, combined with the valve amplifiers of the time, helped define electric guitar as we know it today.

Variations of the were released in several different finishes, including chrome, red and silver. Widely used many classic amplifier manufacturers of the, it was the adoption of the by Vox for their AC30 that cemented its place in history. The Blue has a, character with a controlled bottom and highs, remaining popular and distinctive to this day. Loaded into a single 12" or 2 x 12" cabinet, this legendary loudspeaker suits a wide range of playing styles.