This is a replacement clutch disc for ACT Clutch kit: ZM1-LW01. This kit was designed and released by ACT before Spec Miata changed their clutch rules to the regular ACT pressure plates. This clutch kit uses aluminum within the pressure plate and has a special disc with friction material designed for the aluminum pressure plate, so it requires the use of pressure plate MZ026 combined with ACT Disc 4000201. This disc will not allow the use of normal Miata clutch pressure plates. This kit has very limited availability and is special order.