Tough zirconium grain provides fast grinding and reliable finishing performanceDurable polyester-cotton backing for long lifeExceptional value and performanceContaminant Free (Fe + Cl + S < 0.1%)Type 27, Flap discs are constructed by layering coated abrasive flaps so they wear away and expose new, sharp grainFlap discs increase productivity and reduce total grinding and finishing costs by grinding, blending & finishing in 1 stepThe plastic backings are resistant to temperature extremes, common chemicals and solventsThe hard plastic backings are designed for high strength and rigidity promoting ease of use and long-lifeEncore Plus is also available in a Type 29 Shape