"For Evolution and Twin Cam 88"" engines. This American made high revving XR 750 style inner and outer spring set is complete with titanium top collars and retainers and is designed as direct OEM equivalents to the set offered by the factory. Screamin' Eagle type spring kit includes inner and outer springs, collars and valve keepers. Fits all Big Twin Evolution, Twin Cam 88"" and Sportster Evolution. Manufacturer"