Xray XB4 medium compound chassis side guards
Xray have introduced optional medium compound chassis side guards for the XB4 buggy. Softer than the kit side guards, they are a tuning aid for chassis flex adjustment. The medium-hardness side guards increase the torsional flex, leading to a softer overall chassis assembly and they are therefore recommended especially for low-traction tracks.
Source: Xray [teamxray.com]