Crimp ring removal tool, use to take off copper crimp rings in the event of a mis-installation, cut the pex pipe as near the end of the barbed insert fitting, open the tool to its fullest & place the stub end of the crimp ring removal tool into the fitting, the cutting blade should be on the outside of the fitting & pex pipe, squeeze the handles together so the cutting blade cuts through the pex pipe, remove tool from fitting & peel pex pipe from fitting, the fitting can be reused if not damaged.