Aluminum oxide is durable and the most common abrasive grain * Type 01 wheels are straight (also called flat) cut-off wheels, and are used for peripheral grinding * Free Cut wheels use a more flexible binder than the Long Life wheel, for faster cutting on low-horsepower machines * Reinforced design helps provide safety, strength, and straight cuts * Resin bonds soften under the heat of grinding, releasing dulled abrasive grains