HPI optional slide carb throttle linkage for the Nitro RS4 and RS4 2. This part is needed if a slide carb engine is used. Everything needed to convert the linkage to a slide carb type. This product includes one 2x3.8x4.5mm ball stud (A249). One servo saver set (A390). One shock parts set/ball end #1 (A471). One 2x80mm linkage rod (A889a). One 4x15x0.45mm spring (A889b). Two 2.1x6x5mm stoppers (A895). One 2.5mm pivot (A898). One silver E2 E-clip (Z242). Two 3x3mm set screws (Z700). One installation sheet. There are several parts on the servo saver parts tree that are not used with this linkage set.