Features:1. Usage: The first press and hold the button for 3 seconds to power on the boot, high temperature output 100% voltage - Red Light, 5 minutes later to the middle temperature automatically - Green Light, press the button to control the temperature high - middle - low. Press and hold the button for 3 seconds to shut down.2. Easy and convenient to use. You can directly put it into your jackets, vests and other clothes for warming and heat it by using 5V 2A power source, such as computer, power adapter or power bank(Not included).3. Application Area: clothes, vests, waists, abdomens, pets and so on. Please avoid the central heating wire when sewing. Maximum Temperature is 55 Centigrade (131 Fahrenheit Degree).Foldable and water resistant to a certain degree, heating evenly, washable, but do not immerse it in water for long time.(The cloth is glued together, the long-term immersion is afraid of affecting the adhesive degree of glue.)4. Lightweight and portable, convenient to take with for outdoor camping or other activities on winters. Also applicable to the people who are afraid of coldness, and they will do not fear of winter any more with it.5. Do not let yourself, babies or people who are not sensitive enough to heat. Do not use in wet conditions, please dry before use. It is strictly forbidden to use when there is no one in the room.There is 2-3% difference according to manual measurement.please check the measurement chart carefully before you buy the item. Product Description:Material:Carbon Fiber Heating Cotton ThreadSize:12 x 8cm / 4.7" x 3.4"Thickness(3/5pcs):2(mm)Thickness(8pcs):1(mm)Quantity:3Pcs/Set,5Pcs/Set, 8PCs/SetRated Voltage:5VRated Power:8WThe normal temperature resistance(3/5pcs):15The normal temperature resistance(8pcs):2.5Maximum Temperature:55 Centigrade (131 Fahrenheit Degree) Three Button Red Light(Hight Temperature 55 Blue Light(Medium Temperature 50 Green Light(Low Temperature 45 What you get:3PCS/5PCS/8PCS x USB Electric Heating Pads