Bosch HDS181-01 18-Volt Lithium-Ion 1/2-Inch Compact Tough Hammer Drill/Driver Kit with 2 High Capacity Batteries, Charger and Case 4-Pole High Performance Motor - For maximum power in the most compact size New Patented Gear Train and Clutch - Enables most compact design in its class and lightest weight Flexible Power System - Both DD and HDD are compatible with every 18V Li-ion Bosch battery Ergonomic Grip Zone - Smallest diameter in market enables better gripping and greater comfort New Ergonomic Design - Modified orientation relative to handle increase comfort