Savarez 540 J Alliance HT Classic Classical Guitar Strings High Tension Trebles: Manufactured from a high technology synthetic fiber exclusively for Savarez. These treble strings are unique in the world of classical guitar strings and represent the first major change in material and performance since the 1940's when nylon trebles replaced gut. They have remarkably increased brilliance, volume, and treble response, compared with all conventional nylon trebles. Basses: Wound on nylon multifilament core. Although superficially similar to other bass strings for classical guitar, they have been redesigned to match the acoustic qualities of the Alliance KF trebles and provide a well balanced set.