Baldor Wheels for 12-Inch and 14-Inch Grinders feature high quality aluminum oxide and silicon abrasive in a premium vitrified system. When installing new wheels, check wheels for possible damage. Do not use a damaged wheel. With new wheel installed, all safety guards in place and operator standing away from front of grinder, run grinder for one minute before apply work. Wear safety glasses and exercise caution. Designed to comply with OSHA standards under normal usage.