The Radiantex and Felt Insoles is composed of three layers of space age technology: RadianTex™ on the exterior to reflect the cold, an open-cell foam in the middle layer to act as a reservoir and to lock in moisture, and a polypropylene inner lining to wick moisture away from the foot. Available in sizes 1 to 6. Adjustments can be made to the insole by easily be cutting down to size using a sharp knife and short, frequent strokes.