The Bosch GDE18V-16 Dust Collector for GBH18V-26 Rotary Hammer is a self-contained unit with a HEPA filter. According to independent testing, this integrated HEPA dust extraction system meets OSHA's silica exposure limits for concrete drilling, averaged over an 8-hour day. The HEPA filter captures 99.97% of particles 0.3 microns and larger. This means users don't have to be tethered to a vacuum. The collector has a Dust Eye bit target designed to align the hammer and bit for precise drilling. The collector mounts to terminals on the hammer, allowing use of the tool battery; no extra battery is required. The attachment has auto power, providing vacuum suction automatically when drilling. It has auto power-off with a built-in two-second delay after releasing the hammer trigger, to allow collection of remaining dust. This handy dust collector mounts on the tool and has the dust capacity for over 40 holes using a 1/4 inch bit drilling 6 inch of concrete.