The RH540M SDS Max combination rotary hammer from Bosch provides maximum productivity in all day drilling and chiseling applications. Equipped with 6.1 ft/lbs of impact energy (E.P.T.A.). The RH540M provides up to 39% more impact energy versus the previous model for best in class performance. The RH540M also provides variable speed. This delivers better bit control during application start-up. SDS-max bit system — tool-free bit changes with automatic bit locking, dust protection and maximum impact energy transfer rate Combination dual mode selector — selector knob allows the tool to be switched between rotary hammer mode or hammer only mode Vario-Lock positioning — rotates and locks chisel into 12 different positions to optimize working angle SDS-max bit system — tool-free bit changes with automatic bit locking, dust protection and maximum impact energy transfer rate Combination dual mode selector — selector knob allows the tool to be switched between rotary hammer mode or hammer only mode Vario-Lock positioning — rotates and locks chisel into 12 different positions to optimize working angle