4000/4-34 Dremel 4 Attachments, 34 Accessories Variable Speed Rotary Tool 4000/4-34 Dremel 4 Attachments, 34 Accessories Variable Speed Rotary Tool features a high performance motor for maximum power and performance at all speeds and a variable speed from 5,000RPM to 35,000RPM and electronic feedback circuitry for consistent performance even in the most demanding applications. 4000/4-34 Dremel 4 Attachments, 34 Accessories Variable Speed Rotary Tool features and innovated airflow system with ventilation mechanism that helps prevention of heat build-up for smoother, cooler and quieter operations. 4000/4-34 Dremel 4 Attachments, 34 Accessories Variable Speed Rotary Tool features a slim/ergonomic 360° grip zone for extra comfort and the separate on/off switch and speed dial make for the perfect speed every time.