ZM5-HDR4 2006+ Mazda MX-5 ACT HD 4-Puck Solid Hub Clutch Kit includes a pressure plate, clutch disc, release bearing, alignment tool, and pilot bearing. HD Pressure Plate:Clamping loads increase 20% - 50%. Pedal effort feels stock to moderate. SFI certified to ensure safety. R4 Solid Hub 4-Pad Disc:Recommended for drag and road racing. Race geared disc that would be a little too harsh on the street but perfect for race cars or non-daily driven track cars . This disc is a popular choice for stock based road racing cars. Benefits are: increased torque capacity, fastest shifts, low inertia, good durability but shortened spline life, sharper engagement than sprung hub disc.