Bosch HDS181-03 18-Volt Lithium-Ion 1/2-Inch Compact Tough Hammer Drill/Driver Kit with 2 Batteries, Charger and Case 4-pole high-performance motor for maximum power in the most compact size New patented gear train and cutch enables most compact design in its class and lightest weight Flexible power system: both DD and HDD are compatible with every 18-volt lithium-ion Bosch battery Smallest diameter grip in market enables better gripping and greater comfort New ergonomic design: modified orientation relative to handle increase comfort