A 10 pack of Advantage Zirconia Flap Discs for sale that are 4 1/2 inch diameter. 
These zirconia flap wheels fit small 4 1/2 inch angle grinders.  The discs are 1/2 inch thick with resin coated paper backing. The 7/8 inch arbor hole has a durable metal outer layer and is standard for 4 1/2 inch grinders with the retaining nut.  60 grit zirconia flap discs are considered medium coarse for sanding and polishing steel.