This drill set is awesome! Given that I would have to pay at least $350 to just drill one hole, I saved a lot by buying this kit and drilling the holes myself. I read a review that was very negative. They said they don't work very well. I have not found this to be the case. I planned ahead and brought a pump spray filled with water to keep the drill bits wet, flush out debris and cool them down while drilling. Perfect result! At moderate speed, the drills cut straight through without any problems. They cut very well in concrete. The only slowdown was the rebar at the bottom of the cut slowing down the cut. They were slightly slower in concrete blocks, but this may be due to the 2.5" diameter hole compared to the 1.5" diameter hole. Pros: Inexpensive way to keep a set of drill bits on the truck and keep the cut clean. Very good product packaging that protects the bits well. Cons: The SD adapter worked, but couldn't easily pop out of the SD recording chuck. It was also a bit soft and bent slightly during the drilling process. I will contact Revain for a replacement. I will then use a steel brush to remove the paint from the adapter in hopes of making it easier to work with. So 4 stars, not 5. One more thing worth mentioning. A masonry bit that fits adapters is not designed to be held by a set screw. At first, that worried me. Then I found that it's really good that it's not held but pushed on and into the adapter from the first and strong twist. It was the best design because of the forces experienced by the bits. I would be very concerned that the bit would become permanently stuck if it turned slightly with the set screw tight. I would definitely recommend this product to other professional builders.