ST1.5 Upgrade Disc - High torque sprung disc assembly lined using two unique friction materials that deliver the perfect combination of performance and driveability. A steel backed lining is used on the flywheel side for smooth engagement and less flywheel surface wear. On the pressure plate side, the ST1.5 disc is lined with a segmented sintered ceramic facing. This facing delivers maximum holding found with a ceramic friction material, yet at the same time because of the disc cushion, yields a smooth engagement for daily driveability.