2 Pieces 4 Inch Concrete Stone Ceramic Turbo Diamond Grinding Cup Wheel,12 Segs Heavy Duty Angle Grinder Wheels for Angle Grinder (Yellow)

I bought these to use with my 4-in Makita angle grinder. I am grinding a concrete garage floor and needed these to do all of the edges where the rented floor grinder could not reach. I had a 900 square foot garage and a 160 square foot work room in addition to a 3x6 closet and a couple other areas to grind. I was very surprised to complete the entire job on one grinding wheel. Despite the description that says it is 180 grit, these ground the concrete easily. They are an absolute steal compared to others at the big box stores.

These grinders fit perfectly on my angle grinder. I had to smooth out a cinder block wall with sloppy mortar job. I needed a smooth finish so I could apply ceramic tile. They made the wall smooth as a baby's butt! Now my tile is perfectly smooth with no awkward imperfections!

If you have a low power grinder and aren't in a hurry, these might save you some money. If you have a decently powered grinder and are willing to pay a bit more to get the job done faster with less work, there are better options.I had a project to grind down a concrete door sill. I had to remove between 1/8" to 3/8" of concrete over a 8" x 6' area twice. I started with a similar grinding wheel from Harbor Freight (Bauer 4 In. Diamond Turbo Cup Wheel). I had an assistant running water over the work area, which kept the dust down and the wheel cool, but made a muddy mess to clean up. I completed about 90% of the job and used maybe 3/4 of the grinding wheel, but it became unbalanced which was made worse by the bearing on the angle grinder getting wobbly. I got another cheap angle 4.3A grinder from Harbor Freight (HF), but decided to try these JIAKAI grinding wheels since they cost $10 for two instead of $30 for one at HF. When I started using these they seemed to be cutting much slower than the HF one had. I tried the HF one again (which didn't shake as bad with a good bearing on my new grinder) and confirmed that it was cutting a lot faster. Comparing the surface of the wheels after grinding for a while, it appears that the JIAKAI wheel has fewer diamonds embedded in the steel, and they appear to be smaller. What I did find was that with the HF wheel, since it bites in more and removes material faster, it takes more power and causes the grinder to heat up rapidly. I would spend more than half of the time with the grinder off sucking air through it with a shop vac to cool it off. With the JIAKAI wheel, it doesn't take nearly as much power so I didn't have problems overheating the grinder. I didn't run continuously since I would pause to examine my work, but I didn't have to take breaks specifically to cool it down. Of course it was more tiring because I spent more time actually grinding. I finished up the job with the JIAKAI wheel since I figured the vibration and overheating might wear out my new grinder, and it worked okay. I'm estimating that I used about 25% of one of the wheels to finish the last 10% of the job, so I'd guess that one HF wheel would do as much grinding as between 3 and 6 of the JIAKAI wheels, so with the much cheaper price, the JIAKAI wheels may be more economical (not counting labor).So if I was going to do this project again from scratch, I'd seriously consider buying a more powerful grinder that could handle the harbor freight wheel. It would have been much more tiring doing the whole thing with the JIAKAI wheel, but if I eventually use these two up on small projects and have another small grinding project, I might get another set.Other observations: The JIAKAI wheels gave off an odor that reminded me of burning matches (Sulphur?) that the HF one did not. The flat area in the middle of the JIAKAI wheel was smaller than the nut used to hold it on, so the nut pressed against the angled part of the cup. It seemed to hold it securely anyway, but it wasn't how I expected it to fit.

Very durable for cleaning up mortar on concrete. Well worth the money.

I ordered two for $10 so five each. One blade is grinding concrete so much faster and smoother than the black masonry grinding wheel I pictured that cost just as much or maybe a dollar more at harbor freight. I didn't wanna pay $50 for the harbor freight wheel that's similar looking to this one. But this one's ten times better than what I was using in the same price range

Hose on mist in one hand an angle grinder in the other and about 20 minutes later the uneven concrete was taken care of a la YouTube. Would recommend.

Works great

Works great. One disc was all I needed.