Multiple tested and award-winning construction vacuum cleaner / tradesman vacuum with top features: Smartfix (rail for Systainer attachment), 2 Velcro straps, and professional stainless steel accessories. Designed for the toughest continuous use for dust extraction directly at power tools during drilling, milling, sanding, and sawing operations on materials like concrete, plaster, stone, cement, wood, paints, and varnishes (non-hazardous dust, dust class "L"). A highly intelligent electronics system measures the underpressure before and after the filter (pressure differential measurement "DDM"). As soon as the factory-set underpressure value is undershot, the impulse filter cleaning automatically activates and cleans both filters in succession within 3.5 seconds, without interrupting work. Even the most challenging fine and problematic dusts - such as plaster - are effortlessly removed by the filters.