The Bosch system utilizes a 2nd fan inside the motor housing to pull dust from the work surface into dust container which allows for an easy installation interface between the tool and the dust collection unit. The Dust Retention Port provides significantly less dust leakage, even if the hammer is turned upside down. With the One Touch Dust Container System removal and clean-up is fast and easy. Monitor dust collection through the Dust Collection Window which minimizes the possiblity of excessive dust buildup in the container/microfilter system. With its integrated paper filter, the micro filter system captures the highest volume of all size dust particles, providing reduced exposure to dust. The Bosch 11250VSRD also features an Offset Side Handle making it easy to get into tight spaces. Its light weight and smaller size reduces user fatigue while working over head or for long periods of time. Bosch provides the best Power to Weight Ratio for a Dust-free Rotary Hammer.