Size:1", Obtain superior, fast results with 3Mradial bristle discs. Unique 3 dimensional flexible abrasive design provides for a uniform finish. Use forremoving firescale, heavy cleaning, pre-polishing, texturing and polishing. Open design dissipates heat, unlike rubber wheels. Bonded cubitron mineral abrasive is much harder than most metals. Recommended for handpiece speed between 15,000-30,000.