The frets Subsequently, the frets would be made from fine segments of wood whose upper ridges would be reinforced by small metal slides. These slides helped to prolong the resonance of the strings when the fingers playing the vina pressed them on to the frets. The latter are comparatively high and their base is carved in a convex curve that fits on to the cylindrical surface of the tube. Traditionally, the resinous substance that binds them on to this surface is made from a vegetable resin (ral) mixed with beeswax. The performance of a raga has always been subject to a specific intonation. The binkar - according to their separate traditions - resorted to different means to remain steadfast to the pitches. Some played the desired note – without moving the frets – by playing on string tension. Others gently heated the resin on the base of the fret in order to shift its position for performing the said raga.