Despite all the advancements in cordless rotary hammers, for boring larger holes in concrete, corded tools are still the ones to grab. The newest rotary hammers from Hitachi are a series of large SDS Max tools, redesigned for harder-hitting power and lower vibration. And to add extra performance features and longevity to the tools, the manufacturer is using new AC brushless motors. The circuitry controlling the motor can deal with drops in voltage due to long extension cords or generators, without damage to the motor, and also allows for four digitally controlled speed settings. The 2 1/16-inch Hitachi DH52MEY model also has an internal User Vibration Protection (UVP) feature with a leaf spring attached to a pivoting weight that moves counter to the motion of the tool to reduce user-felt vibration. This model delivers 16.2 foot-pounds of impact energy with a vibration level rated at 9.8 m/s2.