Bosch Bare-Tool CAG180B 18-Volt Lithium-Ion 4-1/2-Inch Lithium-Ion Grinder Powerful 4-pole motor Low-profile gear design Electronic Motor Protection Burst resistant guard Overload protection and lifetime brush design - creates long motor life without need to change brushes Highest Performance 4-Pole Motor - Powers through cutting /grinding applications in metal, masonry and tile. Longest Run Time in class - 25% more cuts per charge. 5 Lbs and 12.6 inches in length - Lightweight design with short length for least amount of user fatigue. FPS and ECP Technology - Tool works with Slimpacks or Fat Packs, monitors battery to reach maximum battery life. 10,000 RPM Optimized Gear Design - Best Combination of speed and power.