Thumb Score: +12 Amazon.com [amazon.com] has DEWALT Flap Disc, Zirconia, 4-1/2-Inch x 7/8-Inch, 80-Grit (DW8309) for $3.49, regular price is $14.58. Shipping is free with Prime or on orders $25+. These things are great for sharpening lawn mower blades, taking paint or rust of metal objects, etc. About this item: Zirconia grit enables 3X faster material removal than fiber resin metal sanding discs Premium abrasive cloth provides up to 15 X longer life than fiber resin metal sanding discs