Bosch Model 1810PS 4-1/2" Paddle Switch Grinder uses a locking paddle switch for better operator comfort and control. Directed air flow diverts dust away from the switch and vital components while the Constant Response Circuitry provides a soft-start and maintains a constant speed under load. Epoxy Coated Field Windings, Service Minder Brushes and Spiral-Bevel Gears enable hard use and easy maintenance.