Works very well when removing thin layers. I would give 5 stars for that. It really helps if you flip the beat from time to time, as some other reviewers have pointed out. However, I bought two. On the second day of use the bit broke at the bottom of the SDS groove causing my bit to break and part of the shank stuck in the body of the hammer drill which I still couldn't get out. I thought maybe a worker used it or a bad hammer drill or something. On the third day that the second drill was used,