This revolutionary system of nasal pillow technology is suitable for side sleepers, minimizing contact with the face and improving mask stability, The Swift FX mask is so soft, light and simple, it feels like it’s not there! The minimal contact with the face and discreet design make the treatment less disturbing and more comfortable. It has 4 sizes: Xsmall, Small, Medium, Large 3 sizes are included in the package (the Xsmall size is available separately).