Usage Information: Standard headgear is provided in all Wisp Mask packages and is the most commonly preferred size. 'RS' Reduced Size headgear is provided in all Wisp Youth Mask packages and is available as a custom sizing option for children and smaller adults. Large headgear is available as an optional item for patients with larger heads. Any headgear size can be used with any Wisp mask. Headgear clips are NOT included.