Bosch SGH182 18-Volt Brushless Drywall Screw Driver Bosch EC brushless motor technology for long lifetime Best combination of power and weight Compact design and light weight for fatigue-free work - 3.5 pounds with 4.0 Ah battery (not included) Longest runtime for continuous work - up to 3,400 screws per battery charge with 4.0Ah (battery not included) Lock-on button for continuous and fatigue-free work