I have a Ryobi angle grinder and usually I use it to cut metal pipes etc. When I saw these flap wheels it is interesting to me as they can be used for polishing or sanding jobs. So I decide to give it a try. It is good for metal and wood. This one is 4 ½ inches wheel with the inner circle is 22mm or 7/8 inches. So make sure this fits your angle grinder before you order it. It comes with 40 packs, 10 packs on each of these grits: 40, 60, 80, 120.Upon opening the package I install the flap wheel on my Ryobi angle grinder and it fits nicely. My first project is to polish my golf clubs. They are so dirty which can’t be cleaned by brushes easily. I use the 120 grit for this purpose. I find that it is able to sand the clubs easily and get the job done fast. I have attached a couple of before and after pictures for you to view. There are sparks coming out during the sanding process. I think this flap wheel may be too heavy duty for this project. Or may be I should use a higher grit number if it is available. After that I check the flap wheel and there is little wear out on it. This shows these flap wheels are quite durable. I also try it on sanding some wood and it cuts into the wood a little bit but get the job done fast.In my view these flap wheels are heavy duty. I also work on car repair myself. I believe they are good for working on cars. For example I think I can use it to remove rust on the cars (pipes, body etc.) easily. And that is probably my next project. With so many wheels I think it is going to last a long period of time. In general I am happy with the quality of these flap wheels.