Automatic Torque Drive Technology (ADT) mode automatically shifts from 3,500-6,500 RPM for extended run time or added power. Steel drive shaft for less vibration and longer life. Reverse rotation function allows operator to quickly clear trimmer head of entangled grass and weeds. Extreme Protection Technology (XPT™) is engineered for improved dust and water resistance for operation in harsh job site conditions. Active Feedback Technology (AFT) automatically shuts down the machine to protect the operator by detecting a reduction in speed such as in hitting a tree stump or fence post.