Bosch IWBH182-01L 18-volt Brushless 1/2-Inch Pin Detent Impact Wrench with 4.0Ah Batteries, Charger and L-Boxx-2 1/2-Inch Pin Detent Drive with Quick Attach: Maximum socket retention with sloped detent provides fast, easy socket attachment Brushless Motor: Up to 2X the motor life, superior efficiency for longer runtime and no maintenance Advanced Electronics: Electronic Motor and Cell Protection help prevent overheating and overloading for extended tool life and runtime Performance Control System: Select between 3 speed and torque settings to maximize power or minimize fastener damage Superior Ergonomics: Smallest grip diameter for best in class ergonomics and comfort