321U | Diameter 5″ | Grit 320 | 100 Discs Per Roll A best-in-class abrasive disc roll for a variety of applications. Engineered ceramic mineral blend is balanced for maximum abrasive performance in its class. Upgraded resins improve durability and finish. Anti-loading coating prevents dust and debris from clogging the cutting surface. Adhesive-backed Stikit discs are easy to attach and remove. No holes.