P-graded aluminum oxide abrasive is durable, and offers a very consistent scratch pattern for the best finish Hook and loop fastener is easy to use and makes disc changes fast Lightweight paper backing can be used wet or dry Vacuum abrasive discs have holes to allow the vacuum sander to pull dust and debris away from the workpiece and sander operator This disc is used with a molded rubber or foam back-up pad (sold separately) Premium heat-treated grain provides 30-50% faster cut rate and extended life Premium B-weight latex fiber re-enforced paper backing is tear resistant, more flexible and provides easier disc removal FEPA P-graded grain achieves a more consistent, uniform scratch pattern The quick-change hook and loop fastening system locks and unlocks each and every time, providing cooler cutting action and a finer finish Pre-punched vacuum assist discs for dust free sanding