Sebo X4AUTOMATIC X models are the most technically advanced and uniquely easy to use vacuum cleaners in the world! The X4 and X4 Boost feature 12 inch power heads and truly automatic height adjustment! An electronic controller measures the resistance of the spinning brush roller against the floor surface and then signals up or down adjustments, to ensure optimal performance on both carpets and hard floors. The user is also alerted to clogs, a worn brush, or