Using the gel pillows sizing gauge (included with the mask or download at the link above), place the pillows cushion tips into the nostrils. Choose the cushion size that allows the blue gel bases to sit comfortably under the nose without any gaps.
Note: Three cushion sizes (small, medium, large) are available. Please refer to your instructions for use for further fitting information.
Philips always recommends consulting a sleep or respiratory therapist in fitting a mask to ensure a proper sizing and fit.