Traxxas heavy-duty chassis brace description: the heavy-duty chassis brace fits slash 4x4 models equipped with the low-cg chassis and all rustler 4x4 models. Made from thick extruded aluminum, the oval-shaped brace increases torsional rigidity and dramatically strengthens the chassis to reduce flex. Brilliantly anodized in four high-impact colors, the hd chassis brace provides structural reinforcement for high loads and hard landings. Whether youre sending it at the skate park, or launching from a ramp, the heavy-duty chassis brace is built for extreme punishment. Accessory part for these models: rustler 4x4 vxl rustler 4x4 slash 4x4 ultimate