• Enhanced electric foot warmers with built-in USB charging design and carbon fiber core to keep feet warm and comfortable. • Three adjustable temperatures: 40-45 °C (blue light), 45-50 °C (green light), and 50-55 °C (red light), adjustable according to your needs. • One size fits all with non-slip design, fits most people and is easy to use with power bank, computer, or adapter. • Made with super soft flannel, thick and skin-friendly material, enhancing the insulation effect. • Perfect for use in the office and at home in winter, an ideal gift for friends and family on special occasions.