ACT Modified Sprung Street discs feature premium organic friction material with higher copper content for better heat transfer and steel-backed lining for greater burst strength and durability. These discs are modified with reduced marcel for faster shift action to complement ACT pressure plates. The heavy duty torsional dampening springs are stronger in most cases than standard springs and are provided in the best sizes and spring rates to suit the application. Modified Street discs allow for quicker shifting and engagement. Quiet operation with increased strength and reliability.