Ashaway Monogut ZX
Ashaway Monogut ZX string is a"polyketone" (polyetheretherketone, PEEK or Zyex® for short). These strings have characteristics that are similar to natural gut strings, but they hold tension longer and are more durable, which means they provide consistent performance for longer periods of time.
In racquet strings, Zyex offers low dynamic stiffness that allows it to deform and recover more completely than other synthetic materials. It can also be made to have exceptionally low creep under continuous tension, allowing racquet strings to maintain tension and playability longer. The manufacturer of Zyex continues to improve and "tweak" the material, making it even better for string applications. Recent advances have produced Zyex filaments that are even finer and stronger than before.