The Rusty’s Frame Strengthener for XJs & ties the unibody frame rails together and helps support and brace the track bar mount. This strengthener is only compatible with the "RC-TB200-UV" Rusty's HD Front Track Bar and HD Frame Mount. Rusty's kits provide great suspension flex, and the increased suspension performance combined with larger tires enables us to test our vehicles on more extreme terrain than ever before. However, all of this increases stress to critical suspension mounting points. The Rusty’s Frame Strengthener spreads the load and stress subjected to the track bar mount across a much larger area of the unibody. Remember, preventing damage is much cheaper than repairing damage!