Hitachi DH40MEY 1-9/16-Inch SDS Max Brushless Rotary Hammer Ultra efficient AC Brushless motor extends product life and eliminates maintenance of armatures or carbon brushes UVP (User Vibration Protection) technology greatly reduces vibration for comfortable extended use and fewer vibration related injuries AHB (Aluminum Housing Body) construction significantly enhances the internal and external durability of the tool Superior performance when using a generator due to an internal inverter circuit that regulates uneven power supply Large change lever located for easy access on top of the tool, rotates for hammer drilling, hammer only or neutral Push button rotation speed selector switch transitions between four power levels of impact and rotation speed to match the application Built-in protection circuit prevents damage to the tool in the event of an abnormality like overload, binding, overheating etc Variable lock mechanism in neutral position allows for 12-angle positions for optimal working angle options Constant speed control increases power to the tool when under load to keep speed constant for smooth drilling Quick release bit system for fast and simple bit replacements for different applications