Street Duty POWER GRIP 900/300 Series Discs: A blend of organic 300 Series and 900 series metallic friction materials that retain all the good engagement characteristics of a full organic disc yet provide a substantial increase in torque capacity. Urethane encapsulated springs in an eight spring hub are more effective in absorbing high shock loads. Use Powergrip discs for higher horsepower or higher torque load vehicles where good driveability is a requirement.