Makita Makita HR4013C 1-9/16" AVT Rotary Hammer Anti-Vibration Technology (AVT) is a Synchronized, Three-Component System that more Effectively Reduces Vibration Resulting in a Low 5m/s2 Anti-Vibration Technology (AVT) is an Internal Counterbalance System that Greatly Reduces Vibration Vibration Absorbing Housing Features a Spring Loaded Main Handle and Upper Housing that Move Independently of the Motor and Drive Mechanism Integrated Damper Spring at the Base of the Impact Bolt is Engineered to Absorb Impact Vibrations from the Drill Bit Powerful 11 AMP Motor Delivers 8.4 ft. lbs. of Impact Energy to Handle the Most Demanding Applications