There are three sizes (S, M, L) of pillow in the package, and the main frame fits all sizes of pillows.
Circular Dispersion Vent
The circular dispersion vent keeps the noise as low as 18dB (A) and meanwhile protects your bed partner from being disturbed.
All Size Kit
Three nasal pillow sizes, namely L, M, and S, come in the package.
Modular Main Frame
The main frame is compatible with all pillow sizes.
The adjustable headgear is fit for most head sizes. Wider range, more inclusiveness.