The Chillr cooling mat works by absorbing heat to reduce body temperature by up to 7?C for 4-6 hours. When in contact with a warm body temperature above 33?C, the filler phase-change material (PCM) melts gradually into liquid as it absorbs heat. The heat exchange process happens naturally without the need for electricity. After use, keep the cooling mat in a cool place, soak in cold water or briefly place in fridge (10-15 minutes) to re-crystallize the filler material, ready for the next use. The PCM filler is a natural substance, is non-toxic and is not harmful to pets.