Air belt sander for use with 0.24 inch x 12.99 inch and 0.39 inch x 12.99 inch wide abrasive belts (4 belts included) Fully adjustable grinding arm with 360 degree rotation for easier use especially in confined spaces Suitable for grinding metal, plastic or wood. Measurement Uncertainty (Standard): 0.56 m/s squared Ergonomically designed trigger with safety throttle and speed control. Free Speed: 20,000 rpm. Handle design insulates against cold air and vibration. Vibration: 0.66 m/s squared. Sound Power Level: 96.5 dB. Sound Pressure Level: 85.5