Sharing all the benefits of the 4000 Series, DBA's 5000 Series rotors are a composite 2 piece direct replacement brake rotor. DBA uses only the highest quality materials to ensure optimal performance under the most strenuous circumstances, combining high carbon cast-iron rings with aerospace grade aluminum hats (T6061-T6), held together with National Aerospace Standards (NAS) bolts and crimp nuts. The 5000 Series share all of the performance technology featured in the 4000 Series, with the added benefits of further weight reduction and improved heat management via aluminum hats. The use of aerospace grade aluminum hats reduces the unsprung weight of the brake rotors, while allowing for uniform radial disc expansion through the cast iron rings, and reduced heat transfer from disc to hub via the aluminum hats. DBA offers both complete assemblies for first time replacement (hats and flat discs bolted together) along with replacement hats and flat disc rotors (rings). This allows drivers to re-use their DBA 5000 Series hats with DBA replacement flat discs (rings). DBA recommends the 5000 Series for high performance street vehicles, track day and club racing and rally applications. Sharing all the benefits of the 4000 Series, DBA's 5000 Series rotors are a composite 2 piece direct replacement brake rotor. DBA uses only the highest quality materials to ensure optimal performance under the most strenuous circumstances.