Features: *Nylon Material: Nylon, also called polyamide fiber, features higher abrasion resistance than all other fiber. And it‘s relatively non-aggressive nature makes the flap discs excellent finishing tools. *Aluminum Oxide Abrasive: Made of chosen aluminum oxide abrasive which provides clog-resistance, fast cut rate, consistent finish *Open Mesh Construction: A web of nylon fibres are bonded together and saturated with aluminum oxide abrasive grains. This produces a cushioned, three-dimensional material that is heat-dissipated, pliable, flexible and long-lasting. Also conforms easily to surface contours and shapes! *Fiberglass Backing Plate: High quality special structure of 8-layer fiberglass mesh screen. Features extra strength, light weight, ability to absorb vibration, and operator comfort *Flat Type 27 Shape: Better work from a 0-15° angle and are the best suited for smooth finishing. The flat-angled flap discs are primarily used on flatter surfaces. Extremely popular and lauded the best select for finishing Specifications: Color: as the picture shows Material: Nylon Abrasive: Aluminum Oxide Material of Backing Plate: Fiberglass Shape: Flat Type 27 Diameter: 4in Arbor: 0.64in Max RPM: 13,300 Grit: 320 Fine Grade. Nylon Flap Discs of this grit are particularly suitable for metal finishing and polishing Machines: Right Angle Grinder Application: Cleaning, Finishing, Buffing-up Application Materials: Stainless Steel, Standard or Alloyed Steel, Non-Ferrous Metals and Alloys Package Contents: 5PCS Polishing Buffiing Wheel