I never see such a Ring (that name), but since gear appear randomized in shops (and elswhere), it's possible to play DD so many times (like me) and still not see all kind of gear that's in DD
What are the specifications of that Sapphire Ring of Fighters ?
Has it a boost to a stat or a skillpoint ?
Where do you bought it, by who ? Can you remember that ?
Welcome to the forums, best of luck, 'O Divine One'