The blades that ship with Rapala Electric Fillet Knives are designed to last the life of the knife. However, on occasion a blade may get lost or damaged from misuse, so Rapala offers replacement blades. Works with all models of Rapala Electric Fillet Knives. Reciprocating Blades: 6" - Works with all models of Rapala Electric Fillet Knives. 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. Compatible with all Rapala electric fillet knives.