The number of holes in a cross-drilled disc is part of the engineered system. Brembo has done extensive testing with regards to the number of holes, their size, their location and their chamfering. This attention to detail is what truly sets Brembo apart in the world of braking. The same attention to detail that is delivered to the Ferrari Formula One effort is a component of the high performance program. The number of holes in a disc is in part a function of the size of the disc and the internal venting (if it is a vented disc).