4-string set for concert ukulele in the key of C (GCEA) from Red series that provides a unique feeling and a strong, consistent sound thanks to Aquila's revolutionary approach which changes the specific weight of the material, increasing it progressively to leave the gauge of strings almost unchanged. That means the instrument sounds brighter, more powerful and more responsive through the entire range of the fret board. The strings also maintain their intonation better, because thicker strings need to be fretted harder, pulling them further out of tune. These strings are made of combination of standard white Nylgut and red copper powder which gives them red-brown colour and slightly rough surface. They do not break under tension providing rapid, stable tuning, have an accurate intonation and are about twice as dense as standard white Nylgut strings. For the Red series strings is not necessary to file the nut slot wider to accommodate them.