Use the Work Sharp Culinary E5 Upgrade Kit to sharpen both 15-degree and 20-degree edge knives. Simply replace the 17-degree guides on the E5 Kitchen Knife Sharpener with either the East (15-degree) or West (20-degree) guides. Then replace the Red P120 Medium sharpening belt with the appropriate belts depending on the type of knife you are sharpening. The E5 Upgrade Kit includes one Blue ZA Coarse belt, two Red P120 Medium belts, one Grey X35 Fine belt, and one White X4 Extra-Fine belt.