Radiator Filler Neck for Mazda Rotary 13B S4 S5 Turbo Model RX7 FC FD Aluminum Radiator Water Neck for Rotary 13B S4/S5, 1.5" Tube Universal for S4 S5 Turbo model , Also for Pre Mazda Rotary Other applications such as single mount turbo Relocation Retains Stock thermostat