Twin Power Extra Plate Clutch Kit For Harley Big Twin / Sportster Features Includes 9 Kevlar friction plates a race proven friction material on tempered steel cores Starburst groove pattern for maximum heat dissipation and oil circulation 8 tempered steel drive plates Pre-set stack height for easy installation Includes 15 stronger diaphragm spring Remove OEM rivet plate 15 more surface area than stock for high performance applications Made in the USA