The Makita 4" Angle Grinder (model GA4030K) is powered by a Makita-built 6 AMP motor that delivers 11,000 RPM for the most demanding applications. The machined bevel gears are engineered for longer tool life, and the all ball bearing design and metal gear housing deliver added durability. The labyrinth construction seals and protects the motor and bearings from dust and debris for longer tool life.