Wet & dry pick up with variable suction control allows for the reduction of suction power if required. Constant suction power even with the finest concrete & wood dust. The filter is automatically cleaned every 15 seconds reducing filter clogging & delivering constant air flow. On/off switch to stop the automatic filter cleaning if required. Reset function automatically activates the automatic cleaning system for the next switch-on. Automatic start & stop control when the power tool is operated. The machine continues to run for an extra 15 seconds to allow all dust to be cleared from system.