Designed especially for flamenco guitars following the indications of Ruben Diaz (pupil and close collaborator of Paco de Lucia) in these strings feature an extra tension - and with a trasparent look that resembles crystal glass, the Sugar Trebles are made using a recently discovered Italian blend of a plastic material derived from sugar-cane. The sound of these strings is clearly brilliant, clean and prompt, and provide great acoustic power. Laboratory tests show that these strings have better sound projection and sustain (24 % and 18 %, respectively) than the Fluorocarbon strings, which gives them excellent vibrato and variation of timbre when played near the bridge and the sound hole. They contain the sweetness and vibrancy of gut and the clarity and promptness typical of Fluorocarbon. Although the surface is extremely smooth, the grip on the fingers is remarkable, in other words it is never slippery.