The Intuition H20 Waterski Liners are designed to improve hard shell waterski boots with added foot retention, comfort, and durability. The Intuition H20 Liners are also a good option for lower volume, tighter fitting mountaineering boots. The Intuition H20 Liners are constructed with lightweight 9mm Dual Density (DD) Intuition Foam that are non-absorbent and fast drying to get you back out on the water sooner.