Features: 1. Suitable for family gatherings, business meetings, bars and other entertainment venues. 2. Built-in 1800mAh lithium battery, easy to carry. 3. It can make the beer foam in the glass and add more atmosphere to the party. 4. Due to the ultrasonic vibration, the beer creates a perfect foam formation, which makes the beer taste better and leaves aromatic residue. 5. The chassis has a silicone pad to fix the bubbler and avoid spilling beer. Specifications: Working principle: ultrasonic Vibration Frequency: 110kHz Operating Voltage: 3.7V Maximum working current: 2A Charging Current: 500mA Battery Capacity: 1800mAh Charging time: 4 hours Instructions: 1. Turn on the toggle switch 2. Activate the tray and pour in half the water. 3. Fill the mug with 60% beer 4. Press the ultrasonic touch button to create foam and the blue light will flash when working. 5. The red light is on when charging and the light is off when fully charged. Package List: 1 * beer frother 1 * User Manual 1*Charging Cable Note: 1. Must put half of the water in the tray, not beer 2. Pay attention to water and beer, try not to splash the touch button, avoid triggering 3. Must be cold beer 4. This product only applies to glasses