What are the cushion sizes of the AirFit N30i nasal cradle mask? How do I know which size to choose?

The AirFit N30i is available in four cushion sizes: small, medium, small wide and wide. To find the right cushion size, place the sizing gauge under your nose. Long, pointy noses will use the blue and red side of the gauge while short, wide noses will use the purple and grey side. Look at both the width and length of the nose on the gauge. If either part of the nose breaches to the second colour, size up to the larger cushion (medium or wide).