Function: 1. The built-in red light that reaches the inner part of the knee can clean impurities in body fluids and blood, accelerate blood circulation and remove joint effusions. 2. Three-degree temperature, thermal energy penetrates the skin, accelerates blood circulation, cleanses the meridians, protects the knees from moisture and cold. 3. Built-in high-frequency vibration motor , all-round knee muscle vibration massage, completely release pressure. 4. Built-in laser infrared sensor lamp, wavelength 615-650NM, wavelength 4-16 nanometers, irradiates the knee joint directly into the deep layer of the knee. 5. LED display, clearly visible, real-time control of massage status, one-button actuation and simple operation. Specification: Item Type: Knee Massager Material : ABS Built-in battery: 3000mAh lithium battery; Temperature: 3 Gear Temperature (40/42/45) Working temperature: 5-40 Relative humidity: 80% How to use: 1. Please fully charge the product before first use. Charging time is about 2-3 hours. 2. Then press the switch button to adjust the temperature, vibration and phototherapy effect according to individual needs. Package List: 1 x knee massager 1 x USB cable 1 x Manual