The thinner gauge means this string is a bit more fragile.
Very thin 0.68 gauge incorporating Vectran technology for excellent power
This string's very thin gauge gives you more precision.
The string gauge is the diameter of the string. The thicker the string, the more sturdy it will be, but the less feel you will have. On the other hand, a thinner string provides more feel but also breaks more easily.
String gauges range from 0.75 mm (very durable) to 0.66 mm (very thin)