This is an optional Traxxas Rustler 4x4 and Slash 4x4 LCG Chassis Green Brace Kit. This 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 high-impact colors, the HD chassis brace provides structural reinforcement for high loads and hard landings. Whether you’re sending it at the skate park, or launching from a ramp, the heavy-duty chassis brace is built for extreme punishment.