I tried out this router bit, and I have to say, I was sorely disappointed .According to my experience, this BIT is not worth your money or time. While it may be labeled "industrial and scientific" it certainly did not hold up to my expectations. The one pro i can offer is that it did, in fact, cut a keyhole shape in my wood piece. However, the con is that the bit broke after only a few uses. Save your money and look elsewhere for a reliable router bit..