This Kit Includes Premium Wheel Bearings with Improved Spring-Loaded Seals and 100% 304 Stainless Steel Axle(s). If Your Machine Needs Wheel Bearings, it is Very Important to Check Your Axles for Wear and/or Rust. Factory Axles are Prone to Rust and Much Softer Than the Bearings. It is Highly Likely That The Old Bearing Has Damaged the Axle. A Damaged, Rusted or Worn Axle Will Significantly Shorten the Life of The Replacement Bearings. HD Switch Axles are Made of Hard Seamless 304 Stainless Steel (304SS) and Will NEVER Rust. 304SS is Harder, Tougher and Will Last Much Longer Than a Soft Carbon Steel Factory Axle. Our Bearings are World Class Quality.