These Nylon Cup Brushes Maintains shape & will not rust，Will not shed bristles under normal conditions. Material: nylon composite grinding sand.So Nylon Bristle Brush safe to use than steel wire brushes, will not puncture skin. Applications: Removing paints, corrosion, weld scale, surface rust & burns from metals.Can also be used for wood polishing and deburring These Nylon Cup Brushes with 1/4 shank fit most drill,Max RPM: 4,500;3 different grit of these abrasive brush to meet different grinding requirements Package include:1×Cup brush red-80#,1×Cup brush gray-120#,1×Cup brush blue-320#;1/4-inch round shank, Max RPM: 4,500 UPC 728458906025 Model FPPO Brand Name FPPO Unit Count 3 Count Grit Number 80 Part Number FPPO Bristle Type Crimped Wire Manufacturer FPPO Item Diameter 3 Inches Material Type Nylon Number of Pieces 3 Grit Material Type Nylon Compatible Material Alloy Steel, Wood