1. World-Patented Clutch Mechanism: more durable and reduce backlash. 2. Steel Alloy Gear Block: high reliability and sturdiness. 3. High Power Rare Earth Material Magnet Motor:smaller dimension, higher torque output, and lower temperature. 4. Patented Brake Switch: high stability. 5. Externally Replaceable Carbon Brush: easy and convenient. 　 6. Spiral Winding Wire in All Model\s Cable: greatly reduces the possibility of bent or broken shafts.