The Seirus Micro Dome? Liner features a thin 4-way stretch fabric that covers your head and ears. The super soft micro fleece band keeps your ears toasty, while the Coolmax? crown wicks moisture away from your skin to keep you comfortable during cold weather activities. This fitted skull cap features flat seam construction and can be worn alone or under a hat or helmet.100% polyester micro fleece ear band. Coolmax? jersey crown with Lycra? spandex binding. Thin, 4-way stretch fabric covers head and ears. Flat seam construction for a comfortable fit. Can be worn alone or under a hat or helmet. Import.