Our customers came up with most of the ideas on these very unique blade guards. These are made out of laminated card stock and is perfect for covering your knives and transporting them in your knife bags or storing in your kitchen drawers. These will handle blades up to 12" long but will work great with smaller ones as well. The sheaths have a ruler, coversion chart for cups, ounces tablespoons and milliliters and an angle guide for sharpening on one side. There is a diagram showing different cuts of a cow, chicken and pig on the other side. Thanks to Shaun Fernandez for doing the layout on this item!