This device has a filter cleaning system and automatically removes the dust stuck on the filter (even during continuous operation) and thus reduces the clogging of the filter in order to prevent a decrease in the suction power. A second filter cleaning is carried out automatically when the unit is switched on or off. When the power is switched on, a pre-filter will collapse, compressing the damper. When the appliance is switched off, it expands to its original size, automatically shaking off the dust from the pre-filter with its expansion force.The battery-powered vacuum cleaner has a mechanism to prevent water from entering the engine when the water level reaches a certain amount of water. When the tank is full of liquid, the device stops automatically. After the appliance has stopped, switch off the appliance and empty the tank. Easy to empty, with a water drain cap.This text is machine translated.