The gentle pressure this pillow emits against the eye lids is an automatic aromatic trigger to your brain to relax and can help ease tension. Each eye pillow is made with 100% cotton material, and filled with a blend of rice, flax, and lavender flowers as well as organic therapeutic grade essential oils. This eye pillow can be used warm or cold. To heat, place in microwave for 20 seconds. Make sure that it's not too hot before applying it to your eyes. To cool, place the pillow in it's plastic protective sleeve, and put in the freezer.