Eventually even the toughest blades get worn out. With the Rapala Guide Fillet Knife that fact isn't a problem. Simply take the old blade and exchange it with a replacement blade and you're back on your way to filleting fish with ease. Blades are made using hand ground stainless steel. Available: 6 or 7-1/2 . Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Replacement Blades.