Extreme H2O 59 Xtra is a problem solver for patients who experience significant dryness and discomfort, and need "Xtra" durability and handling benefits provided by a slightly thicker lens design. Extreme H2O 59 Xtra retains 99% of its water content on the eye, even under extreme conditions. All lens dimensions and oxygen permeability present in the first hour of wear will be present in the last. Lens comfort, movement and fit will be stable throughout the day.