This Top Shelf Professional Knife Sharpening Guide positions the knife at the perfect angle for sharpening & is ideal to use with sharpening stones for fast precision sharpening. Featuring a ceramic protective strip for durable use, this guide provides an operating sharpening angle of 15° which is the optimum angle for sharpening knives. Perfect for those of us who are challenged trying to keep the correct angle when sharpening on a stone, simply clip the guide to the back of you knife & rest on the stone whilst sharpening.