Neiko 30100A 4" Angle Head Air Powered Grinder with Safety Throttle Equipped with a free speed of 11,000 RPM and 90 PSI ideal for buffing, removing rust or smoothing surfaces in preparation of welding Precisely machined steel construction withstands tough metal work for durability and long lasting tool life Built in blade guard protects your body parts from engaging with metal cut off disc while in action Grip controlled handle is equipped with a safety-lock throttle lever to prevent accidental startup Powerful and quick grinder is perfect for metal work and cuts into concrete, bolts, rebar, sanding work and much more