Diablo DCD050040P05G 5 in. 40-Grit Random Orbital Sanding Disc with StickFast Backing (5-Pack) 5-inch sanding disc 40-grit paper Premium ceramic grain blend is a superior quality formulation designed for fast material removal and long sanding life Stickfast backing, an industrial-grade Pressure Sensitive Adhesive (PSA) backing for a strong and secure bond Clog-SHIELD, a proprietary blend of grinding agents that reduce pitch build-up and clogging