Girodisc Nissan GTR 390mm Replacement Rotor Ring PairOur replacement rings are sold in pairs and include replacement hardware. The only parts you will reuse are your existing GiroDisc hats. Please note that unless specifically noted, GiroDisc replacement rings are only designed to work with GiroDisc hats. They are not designed to be used with other brands, including hats from cars equipped with 2 piece rotors from the factory.