The unique shape of this pillow promotes proper neck and spinal alignment, especially when using a CPAP or BI-PAP device. The pillow can be used to sleep comfortably on your side, back or stomach. The mask and hose can move freely with the patient due to the ARC cutout in the pillow. The pillow is filled with a hypo-allergenic, high-lofted, polyester fiber and covered in a white on white poly/cotton cover. An additional cover is included.