This 215mm 4 puck unsprung center disc is for race ues only.  This disc is more aggressive with minimal slip and no time lost shifting.  Unsprung discs are half the weight of sprung center discs, using the same two organic compounds as the sprung disc .  These materials make it possible for a civilized take off in first gear.  It is surprisingly manageable in my SCCA ITB Spider.  This disc and the aluminum pressure plate saves nearly four pounds of rotating mass!

For Clutch/Flywheel weights and specifications, see "Additional Product Information" Section.