For the price I have in fact no real quality expected. My claim was to cut 10-20 holes, especially the masonry is quite pliable and then send the part in the well-deserved retirement. In fact, after two holes, the retaining screw was so ausgenudelt that the things is now worthless and the price for it is then too high. I can only recommend, with little possibilities the holes with a hammer and chisel or similar to make, to borrow a good bit for the price and otherwise but to buy a professional crown.
