Ashaway’s ZyMax family of strings features their BETA Polymer ZyWeaVE core with a similar BETA Polymer surface and coated with a bonded texture to allow for greater control and “grip” of the shuttle. That all sounds fancy but what it basically means is that their ZyMax strings perform exceptionally well for both power and control. The 68 TX and 64 TX series represent their string diameters at 0.68mm and 0.64mm respectively. The 68 TX is thicker and provides more durability while the 64 TX is thinner and has better repulsion characteristics (power). Hitting with both strings feels incredible as they have a very crisp hitting sound and feel.
Our recommendation is that if you are an intermediate-level player who wants a well-rounded string that offers durability and more power-centric characteristics, go with the 68TX. If you are a bit more advanced or are a serious control player who knows how to get power from their swing and sweet spot, then go with the 64 TX!
The string price includes labor for stringing.