Sea to Summit Expander Travel Liner

The primary purpose is hygiene and comfort. It keeps your sleeping bag cleaner by acting as a barrier against dirt and oils, and it provides a familiar, soft surface when you are staying in hostels, hotels, or unfamiliar beds.

It uses a jersey-knit blend of cotton and polyester, which feels much more like a soft, stretchy t-shirt than a crisp cotton sheet. This stretch allows the liner to move with you rather than restricting your movement while you sleep.

Yes, the treatment helps inhibit the growth of odor-causing bacteria. While it doesn't replace the need for washing, it keeps the liner feeling fresher for longer during extended trips where laundry access might be limited.

It is designed to eliminate pressure points and friction that can occur with side seams. You will likely notice it feels more spacious and less restrictive than a traditional rectangular liner, especially if you tend to toss and turn.

It is fully machine washable. Simply toss it in with your regular laundry on a gentle cycle and hang it to dry or tumble dry on low heat.

While it is primarily designed for comfort and hygiene, the knit fabric does provide a slight layer of insulation. It is not a high-performance thermal liner, but it can add a few degrees of warmth to your sleep system.