Medibeads produce moist heat by absorbing water molecules from the air. When activated in the microwave, these molecules are released in the form of clean soothing heat. Designed to relieve tight, sore muscles resulting from stress, tension, and prolonged static activities. Each contoured wrap is covered in a soft, plush fabric, and conforms to the shape of your body to maximize relief. other moist heat products absorb body oils, product odours, or encourage mold and fungal growth, but anti microbial Medi-Beads stay clean and odour free! Microwave for approx. 1 minute and the wrap is ready to use for up to 30 minutes. Material: 100% polyester. Wait 2 hours after use before cleaning. Hand wash or surface clean in cold water.