High Performance Extra Plate Kit 1990-1997 Big Twin and 1991 to present Sportster (XL). Includes nine aramid fibers friction plates on tempered steel cores. Starburst groove pattern for maximum heat dissipation and oil circulation. Included are eight tempered steel drive plates. Preset stack height for easy installation. 15% more clutch area for high performance strokers. Includes 15% stronger diaphragm spring. Remove OEM rivet plate! 15% MORE SURFACE AREA THAN STOCK.Stack Height: Frictions and steels 1.275 - 1.290"