Fits Big Twin 1990-1997 and Sportster 1991-Later. Designed for big inch engines, this extra plate kit provides 10 percent more surface. Designed for big inch engines, this extra plate kit provides 10 percent more surface area than OE clutch. Carbon based friction material (carbonite) by 3M bonded to 10 steel disc. The nine drive plates feature a Melonite Kolene treated to the steel base by a nitrite process producing a heat resistant finish that is compatible with carbinite. Eliminates the need for the OE style double riveted steel plate. Lifetime warranty.