Z-Prime Korner Flap Discs Are Available In Turn-On Version In 2-3″ Sizes. Korner Z-Prime Flap Discs Will Outlast Competing Quick Change Discs By Up To 6-1. Korner Unique Design Will Allow For Product To Be Used In “Korners”. Z-Prime Has Poly-Cotton Backing Which Allows Excellent Flexibility. Z-Prime Provides Cool Cutting With A Built-In Grinding Aid To Provide Cool Cutting With Light Pressure.