The RH540S 1-9/16 in. Spline Combination Hammer from Bosch provides maximum productivity in all day drilling and chiseling applications. At 6.1 ft. lbs. of impact energy (E.P.T.A), the new RH540S provides up to 30% more impact energy versus the previous model for best in class performance. The RH450S also provides variable speed for better bit control during application start-up.