[Improved Design] After reviewing all the complaints about the grinding disc set, our engineer improved the center hole diameter to make it compatible with 4" and 4 1/2" angle grinders. The grooves of the wood grinding disc were enlarged to fit the widely used 1.61" black flange nut, so all parts work right out of the box. [Fits 4" or 4 1/2" Angle Grinders with 5/8" and 7/8" Mount] The angle grinder attachment set includes 3 wood grinding discs (4" diameter × 7/8" bore) and 3 silver bushings (7/8" to 5/8"). Designed for use in all standard 4" or 4 1/2" angle grinders with 5/8" as well as M10 mount, such as: E.g. Makita, Bosch, Dewalt, Black & Decker, Milwaukee, Hitachhi and more. [Suitable for Various Occasions] Hundreds of aggressive teeth of the wood grinding disc can remove paint residue and rotted wood to smooth the surface of old furniture. More durable than hundreds of sandpapers, saves energy and improves work efficiency. [Practical Woodworking Tools] With its fast polishing