Revo's linkage-based suspenciosn requires different push rod assmeblies depending upon which rockers are used, Strong, 7075-T6 aluminum versions of each are available to decrease teh total weight of the truck by 31 grams.  Rod ends are already snstalled making it simple to just bolt them on the truck.  When using progressive-2 rockers, spacers (TRA5133) are required for use with the TRA5318 or TRA5318X push rods.  These spacers are included with the progressive-2 rockers.  (For use with TRA5357 Progressive -1, or progressive-2 rockers.)