The 9564P 4-1/2 in. Angle Grinder combines a Makita-built 10 AMP motor with best-in-class durability features to deliver more output power and increased performance. The 9564P is ideal for welders, fabricators, ship yard contractors, masons, electricians, automotive technicians, stone and tile contractors, HVAC, and more. The 9564P is equipped with SJS™ mechanical clutch syster, a Makita innovation engineered to protect the motor and gears. With SJS™, the drive shaft from the armature to the drive gear is spring-loaded during normal grinding load. If binding occurs or the wheel is forced to stop, the spring is compressed, which allows the drive shaft to slip. The result: gear tension is minimized for longer gear life as the armature continues to rotate, which helps prevent motor burn-out. The motor-protection function of SJS™ is mechanical, not electronic. This is a key point-of-difference, as the mechanical function does not require the contractor to stop and re-start the tool in the event that the wheel is forced to stop. With an electronic clutch, the tool requires a re-start. The 9564P is distinguished from other grinders in its class by three innovative dust and debris defense features. First is Labyrinth Construction, a series of channels engineered to capture dust and debris. This prevents contaminants from penetrating the gear box and main bearing. A second feature is Makita’s unique “zig zag” application pattern, which is a more innovative option than simply covering the coils with epoxy. The zig-zag pattern allows space for heat to escape, yet at the same time the zig-zag pattern forms a solid barrier under rotation to prevent debris from attaching. Finally, the Dust Sealed Drive Bearing is a spring-loaded metal seal is engineered to stop dust and debris from entering the drive bearing. Additional performance features include a larger cooling fan and blades, which pull more air through the motor to help maintain lower operating temperatures, as well as spiral bevel gears for smoother rotations and a more efficient transfer of power.