These are made much stronger than the factory shackles and have a thicker metal material used for heavy duty use and longevity. The bushings are rubber encased and pressed in. Meaning it's a one piece, that has a rubber outside and a metal tube inside for the bolt. **Same type of rubber durometer you would find on factory.** This feature is key when maintaining a smooth ride and durability. The materials used, and bushings in these are far superior than what comes in most aftermarket shackles. That is why this shackle is considered a "premium shackle" and separates itself from the rest.