Most people associate the name neoprene with diving suits and water sports in general. Neoprene is a synthetic material, also called chloroprene rubber, which has excellent thermal insulation. A large number of small bubbles provide optimal thermal insulation. Since neoprene is waterproof, it has also been used successfully for years as a lining material for rubber boots. The neoprene is able to keep the temperature in the rubber boot comfortable. However, it is very important for neoprene lined rubber boots to be in a warm or, in summer, cool ambient temperature before wearing them. If you step into a cold neoprene lined boot with cold feet, your feet will stay cold. Neoprene is not able to heat up the feet, only to maintain the temperature. If you step into a warm rubber boot in winter with warm feet, your feet will also stay pleasantly warm. Neoprene stores and maintains temperature, unlike lambswool which is able to warm a foot. Neoprene linings are available in different thicknesses and have correspondingly higher insulating properties.