The Breeze Sleeping Bag Liner comes in Mummy and Rectangular versions. Its stretch-knit fabric offers freedom of movement and wicks moisture with a 70% Coolmax Ecomade and 30% Tencel Lyocell blend. The Mummy model includes Insect Shield treatment to repel bugs. The Rectangular version has a built-in pillow sleeve sized for an Aeros Pillow. It provides a hygienic sleep environment in various conditions.