YoYoStringLab - Type X
This medium thickness string keeps its color and tension longer than any other string on the market. This string plays at super fast speeds, but still gives the control over harder tricks that slower string provides. Each string is made with amazing accuracy meaning that you won't have to worry about different batches of strings being slightly different from each other. It also lasts much longer then the average yo-yo string.
This string can give players of all levels that extra bit of consistency you need to reach the next level.