The Del-a-lum shackle kit rates far superior over poly or stock rubber. While poly and rubber allow spring eye bind, causing the rear end to break loose, these Del-a-lum bushings keep your rear leaf springs from binding. No other bushing is designed to allow proper lubrication, like the Del-a-lum, insuring a quite ride and longevity. Backed by Global west this bushing comes with a limited life time warranty, and will work with any leaf spring that excepts stock multi-leaf bushings.