I bought the 6 1/2" square and the strip peeled off the first time my blade got near it. It didn't sharpen my blade (didn't have time to even try) but I really like the lines on it as they are easy to read and mine (Sullivan's Edge) has lovely red lines clearly marked for squaring up blocks and HST's smaller than 6 1/2". It was on sale and worth the price but I'm not using it the way it was intended.