The self heating pad for neck will heat slowly after contacting the air, and the temperature will reach 107.6 Degree F within 15 minutes , its effective time can reach 4-6 hours. If you feel it doesn\'t work, please wait patiently, because it won\'t heat up immediately!Wear neck pain relief heating pad to relieve pain and discomfort. How to use Step 1 Remove the pad from sealed pouch.The pad will be warm up when opened.Use immediately. Step 2 Wear the pad with the white surface facing you,making contact with skin. Step 3 Put the Velcro on gently and adjust it to be comfortable. Discard after use. IngredientsLavender essential oil,Iron Powder, Activated Carbon Powder, Salt, Vermiculite, Water, Cotton, Polyester, Polypropylene. Matters needing attention: Do not use when the skin of shoulder and neck is damaged. Due to different skin sensitivity, if you feel high temperature or discomfort, please stop using immediately. The length of the pad is 19.7 inches.If the pad doesn\'t fit around your neck, you can try 19.7 inch+silk scarf.19.7 inch+silk scarf has a silk scarf inside to help you secure the pad. The heating pad is not suitable for people under 10 years old. This self heating wrap is a disposable product and is invalid for repeated use. If you\'re unhappy with our neck heated pad for any reason, let us know. You\'ll get a full no questions asked refund on your purchase. WhyWe\'re sure that with proper and intended use, you\'ll love this product as much as we do.