Electronic management system (EMS) protects the machine, extends service life, and increases efficiency. Brushless motor with higher efficiency and longer service life. Microprocessor electronics include speed preselection, speed stabilization via tachogenerator, soft start, restart interlock after power failure, overload protection, and temperature monitoring. Unique tool attachment with quick coupling allows for tool-free change of the four system attachments for satin finishing and pipe belt grinding, as well as grinding with belt file or fillet grinder. Tool-free attachment change is facilitated by a patented quick-change system. Perfect dust protection is provided by a detachable metal guard. Features an LED battery capacity indicator and spindle lock. FLEX battery system allows operation with all 18.0 V battery packs.