A Protector is a held item that is needed to evolve Rhydon into Rhyperior. If Rhydon holds a Protector while being traded, the Protector will be used up and Rhydon will evolve. It can be obtained as a tier 2 special drop or from a Rhyperior.
This item originally had a crafting recipe, which was this:
(This recipe is no longer in use)