Black Diamond 6 Groove Discs are engineered and made using computer aided design and manufacturing to ensure they are finished to the most exacting standards.The 6 curved radial grooves on each disc face help dissipate heat and de-glaze the pads, offering greater friction under hard braking condition and making them less likely to fade. The result is better pedal feel and improved brake response.The unique compound and heat treatment after machining combine to provide awesome braking performance that will improve stopping power and give longer lasting durability.They also look great behind wheels !Supplied as a pair.Please Note -The coating on these discs will wear off the surface swept by the pads.