These are the Tamiya Stabilizer Rod Stopper. Tightens handling and inproves stabilizer function. Snazzy blue anodized aluminum finish adds class. When using sway bars in a touring car sedan it is critical to fix the sway bar onto the chassis as secure as possible without binding the bar. These stoppers are used to prevent the sway bar from moving left to right under load. A sway bar should move freely up and down, but should not move from side to side. These stoppers prevent that from happening and allow the bars to perform their function correctly.