Pillow Core Material: This pillow core is made by premium memory foam. The feature of slow rebounding will make pillow suit to shape of head on higher level. Design: 14cm High Side - Your wider shoulder will need such a high side from the pillow. Central Groove Design - Depression in the middle help back sleepers get lower position of head, which helps avoid straighten natural curve of neck. When putting head on pillow, your neck is lifted about half inch higher than head. Wider -The wedge-shaped extensions perfectly fit the outline of face and neck for side sleepers, and specially designed 60 angle bottom of pillow would spare room for your shoulder. FUNCTION: Reverse slope keep your head on same line with spine to prevent stiff neck for side sleepers. Tiny cavities on cover provide skin-friendly feeling. Low noise of memory foam ensure peaceful and cozy sleep.