No, the POWERBREATHER is currently only available in one size. However, it can be optimal adjusted with the innovative AMEO TWIST LOCK SYSTEM for individual head sizes of adults. Experience shows that the POWERBREATHER can be adjusted without any problems to the individual head size of youngsters and children from the age of approximately 12 years. For extremely round head shapes with a width of more than 17.5cm the currently available Powerbreather may possibly pinch a bit at the sides. The D-Tubes should not be pulled apart beyond 17.5cm head width; otherwise the POWERBREATHER can get damaged at the EASY FIT AIR JUNCTION.