Safety clutch protects user from injury and power tool from overloading, suitable for diamond core bits up to 152 mm, 2 mechanical gears, variable speed control, "D" handle for improved comfort and grip, reverse rotation via rotating carbon brushes for direction change - longer service life and higher motor power, electronic switch with stepped thumbwheel for optimum speed control, switchable on-off percussion action facility allows easy drilling of pilot hole in masonry, ergonomic anti slip grip design. CAUTION: never use a diamond core bit with percussion action engaged!