Makita 9557NB2 4.5" Angle Grinder with AC/DC Switch 2 Pack has a labyrinth construction that seals and protects the motor and bearings from dust and debris for a long life, with an additional, protective zigzag varnish that seals the motor from contaminants by forming a barrier under rotation. This UL-listed grinder provides high-output power with its 7.5 AMP motor that maintains a 11,000 RPM speed to produce excellent grinding with a 2-1/2 in. small-circumference, barrel-grip handle for added comfort. All ball-bearing design and metal gear housing provide durability.