Tracked and grooved upper guide / backplate interface increases stiffness and eases installation New co-molded "HD2" upper guide with softer durometer interior for silent guidance Integrated skid protects chainrings and glides over rocks and obstacles Includes standard pulley and G-slide slider block for quiet, dependable operation in muddy and dank conditions. Oval compatible Mounting hardware included and install possible with just a single 4mm HEX wrench. Swingset™ hardware. Compatible with chainlines 50mm and wider ISCG-05 only From 1945g