CRAFTS4U Craft Knife Refill Blades fit the Crafts4U Craft Knife as well as many other craft knives including the Fiskars Finger Tip Craft Knife (not the Fiskars Swivel Knife). The refill blades come in a sturdy clear plastic storage container to keep all your spare blades together. Crafts4U Refill Blades (10028) and can be replaced by carefully unscrewing the clamp on the Crafts4U Craft Knife that holds the old blade and replacing with a new blade and retightening the clamp. Please dispose of the old blade in a safe manner such as wrapping in sticky tape. Also store the spare blades and craft knife away from children.