AQUILA RED SERIES ukulele strings provide superior performance over traditional strings for musicians who love bright sounds and powerful voicing across the full scale of the instrument. You never heard a sound like this before, simply because before it did not exist. Why the strings has different shades of red? In the manufacturing process of our Red Series strings we use different percentages of metal powder to optimize each string’s performance within the set. Because of this, the color varies slightly with each string in a set of Reds. This is not a production problem. It is so each string produces the sound you expect from Aquila Reds! Attention! The Red Series strings must be stretched by your fingers in a gentle way. The settle up in tune in 2-3 days.