Dremel 4000 variable speed rotary tool offers the highest performance and most versatility of all Dremel rotary tools. The increased strength of its motor plus electronic feedback circuitry enables consistent performance at all speed levels. Ergonomic and slim body provides a 360 degree grip zone for comfort and control in any grip position.| High-performance motor for maximum performance at all speeds.| Electronic feedback for consistent speed under load.| Variable speed provides maximum control and precision.| Separate on/off switch and speed control dial for the perfect speed every time.| Quick collet lock for fast accessory changes.| Cool-running ball bearing construction for smooth and quiet operation.| Replaceable motor brushes extend tool life.