As a vintage tool collector, I often buy tools that have long since passed their due dates. A fellow collector and woodworker suggested my life would be a lot easier bringing old plane irons and chisels back to life if I bought the DMT diamond plates (I have trouble calling them stones). I started out with a couple and realized I was going to need a few more to get the most of them, so I bought a couple more, then a couple more. Yup. I bought all six of the 3" x 8", and I can't tell you how pleased I am with these plates. Wow, do they work, from the extra, extra course 120 grit, which removes unwanted metal quicker than anything I have used to date, to the extra, extra fine 6000 grit, which gets the sharpest edges possible. Great stuff!