Review on LOT Pcs Diamond Hole Drill Bits - Cutting Tools by Carl Higdem

Worked great. Much better than the expensive ones I bought thinking they would wear out. I only really needed a few sizes but the kit was cheaper than buying those two pieces. I had to buy two sets as I had 6 drill holes in granite and 8 drill holes in marble. One of these nozzles made 4 marble holes with no problem. The larger size also made the other 4 no problem. Then I used a more expensive drill bit I bought for granite. It was 1 1/2 times the price of this entire set. I drilled a hole in them and went back to these. The penetration rate with them was much better. I finished the remaining 5 holes in the granite with a drill that I used to drill 4 holes in the marble. He made all the holes, but he wouldn't make another one. It was definitely worn out. They don't have a central lure, so you have to start them from the edge and slowly roll them down. It takes a bit of technique.