I used this product to cut a 4 inch hole in my foundation for a dryer vent. I needed to raise the vent higher so I went to the top rough block. They built a house from the shell and filled the upper large one with cement. The saw cut through really well until I came across some metal rods that they had also set into the wall. At first without realizing I kept trying thinking I hit the rocks I realized it was bigger then I went outside and went inside. This blunted the saw but still worked. For the money they are worth buying.