Brembo Application Guide 14-19 991 GT3, 991 GT3RS (Excluding PCCB) Manufacturer Notes This system consists of 2-Piece disc assemblies which directly replace the OEM discs. To be used with OEM calipers. | The disc bells in this system are finished in natural hard anodize, exhibiting a greyish color, different from the black used on most GT systems. Disc Information Disc Type: Slotted Type-3 Disc Material/Finish: Advanced High Carbon Alloy / Corrosion Resistant Plating Disc Diameter: 380mm Disc Width (Measurement): 34mm Disc Construction: 2-Piece Disc Assembly Disc Vane Design (Measurement): Vented Curved 72 Vane Disc To Hat Mounting System: Floating D-Bobbin with Anti Rattle Spring