Polyester | Designed for CPAP users with contoured cutouts that increase comfort by reducing mask interference and allowing hoses to position themselves naturally; A built-in hose tether allows the hose to move easily with you during the night. | A molded sunken area opens the airways for comfortable, full breathing for an amazing night’s sleep; The pillow has three removeable/addable layers to customize your sleeping height based on your preference. | High-rebounding memory foam gently molds to the mask and face without falling flat and uncomfortable after repeated usage; Supports side, stomach, and back sleepers. | Two different sides for sleep preference; Choose the cool and dry ventilated memory foam or turn the pillow over for the plush, fiberfill side for your choice in comfort. Both sides offer support for the neck, spine and shoulders to align naturally.