Bosch DG490CE. . Features: High-torque gear box provides more power for the toughest applications. Variable-speed dial provides the ability to adjust speed for specialty applications. Hardened 1/4 in. collet for longer life and increased precision. Lock-On slide switch easily locks on tool for extended use applications. Extended spindle for grinding in difficult to reach places. Constant-response circuitry provides a soft-start, maintains constant speed under load and provides overload protection. Direct air-flow diverts dust away from vital components and extends tool life. Metal gear cover for maximum durability. Service Minder carbon brushes eliminate guesswork and increases lifetime for less downtime with auto-cutoff when brushes need service.