Powerflex polyurethane bushings are designed to decrease the amount of deflection in your car's suspension for better handling, driver feedback, and tire wear. Powerflex uses premium polyurethane materials for minimal NVH (noise, vibration, harshness) and increased longevity over the stock rubber bushings. Copper-based grease is supplied with every dynamic product. We suggest using only a copper-based grease for lubrication. Due to grooves cast into the material to hold the lubricant, bushings will rarely need re-lubing.