These bastards are amazing. At first I thought they might be defective. Everything I do turns out to be of terribly poor quality. Measure twice, cut four times, I'm right. I realized very quickly that if I just tilted the level until the bubble was in the center and then applied it, it would be a magic spirit level! And it has helped me win so many customer disputes. They always complain that their items aren't level, I just show them a bubble and tell them to shut up.