Del-a-lum bushings are designed to control lateral loads as well as provide smooth up and down movement without bind. Inserts & thrust washers separate the housings and springs from metal-to-metal contact and provide total isolation. Each bushing can belubricated without disassembly via grease fittings. Fits stock 1964-1966 leaf springs only with the smaller size eyelet. Most all aftermarket springs have the larger eyelet and use kit RSK6.