This authentic replacement part is specially provided for use with Chicago Pneumatic power tools. Ball bearings are used to reduce friction between rotating parts, the rollers help distribute the weight evenly while the minimal contact area of the ball reduces friction. Bearings experience constant wear from pressure, heat, vibration and ...Read morefriction, because of this, many bearings need to be periodically replaced. Please make sure to check appropriate diagrams of your model for correct location and use of this item. This high-quality part is made of durable metal and it is sold individually.