Nylon Screw threaded hub for easy mounting to the backing pad.High durability with superior edge retention and minimal smearing.For aggressive applications where traditional surface conditioning products fail.Ideal for highly contoured surfaces, heavy blending and finishing and sharp edges., Coarse (Brown): Excellent for heavy deburring, removing weld spatter and blending tool/mill marks, rust removal.Medium (Maroon): Excellent for light deburring, blending scratch patterns, removing coating/adhesives.Backing Pads for Non-Woven Discs are available in Accessories.