These are cheap and inexpensive. The low cost and acceptable performance make these a good tool for a budget minded shop. I would buy nicer if I used these regularly, but I dont. I have not had a need to use the included clamps yet. They seem very light duty and not sure I would trust them in a milling machine. I just use the blocks for quick little jobs that do not require extreme precision. If you plant to manufacture precision parts using V-Blocks I would recommend looking for better. The finish is not perfect but decent, thus four out of five start.