The Seirus Innovation Micro Dome liner is made from super-soft microfleece jersey with a crown that wicks moisture away from your skin. This fitted skull cap features flat seam construction and can be worn alone or under a hat or helmet. The thin, 4-way stretch fabric covers your head and ears, and fits comfortably under a hat or helmet. The Seirus Innovation Micro Dome liner features flat seam construction, making it the perfect liner.