Royal Classics RC20T Futura Nylon Guitar String Treblepak, Medium Tension Royal Classics specialty treblepaks are perfect for matching with your favorite bass strings The RC20T Futura treblepak includes 3 medium tension transparent nylon treble strings, gauged .73 mm /.029", .83 mm /.033", 1.04 mm /.041". Crafted in Spain by and for serious guitarists.