Charging case and power bank: The earbuds come with a charging case that has a built-in power bank. Various product descriptions list different battery capacities for the charging case, from 1200 mAh up to 3500 mAh, but the power bank feature is a common selling point. Some sellers state that the case can also be used to charge a smartphone.
Digital LED display: The charging case has an LED screen that displays the battery life of the case and the earbuds.
Controls: The earbuds feature touch controls for managing music playback, volume, and phone calls. There may be versions with physical buttons as well.
Connectivity: The earbuds use Bluetooth 5.0 or 5.1 technology and have a working range of about 10 meters.
Water resistance: Most versions have a water resistance rating, such as IPX7, though some listings mention lower ratings like IPX4. This makes them suitable for workouts and can protect them from sweat and rain.
Noise reduction: The F9 earbuds use CVC 8.0 noise reduction for calls, and have some passive noise isolation.