Our MOSOS semi-metallic brake pads are developed under American and European top technology, are combined by primarily of resin and 30 to 60 percent metal. Even though it consist of most metal, but its not hard as it looks. The average hardness of ours MOSOS semi-metallic brake pads are around 90. So it wont hurt brake disc at all. In the past, many of these semi-metallic brake pads were comprised of asbestos which are very dangerous to human health and environment. All of our MOSOS brake pads are completely asbestos free, making them both safe as well as long-lasting. The graphite, resin and metal composition of these brake pads are less wear, making the long-lasting longer life. Advances of MOSOS Semi-Metallic Formula ï?¬Less noisy ï?¬Cleaner rotor ï?¬Longer pad & rotor life ï?¬Smooth braking feel & predictable control ï?¬Short braking distance ï?¬27 °C-650 °C operating temperatures ï?¬27 °C-400 °C optimal temperature range ï?¬All Roland brake pads are not compatible with carbon ceramic rotors. Roland pads are designed to work with Iron/Metal rotors.