This tool allows you to restore the shape of a bent ring. 

To use it, first place the ring on the conical piece, then attach the other piece designed to press the ring back into shape. 

For better control over the applied force, you can secure the tool in a bench vise and tighten it slowly. It is also advisable to apply a small amount of lubricant to both pieces and the ring to ensure smoother movement. Extra care must be taken, as applying too much force could break the ring.