Brushless Backpack Vacuum, 0.5 US Gal. (1.9 Litres)Two stage HEPA filtration system captures large, small and micro dust particulates and is certified to 99. 99% efficiency (0. 01% permeability) at 0. 3 0. 5 microns (m) Brushless motor is electronically controlled to create less heat and provide a high power to weight and size ratio, making it ideal for prolonged periods of use Backpack design with adjustable padded shoulder pads and waist belt offers unparalleled comfort, maneuverability and