If your blade is wider than the safety sleeve, don't worry! Just make sure that the sharp part of the blade is aligned with the closed part of the sleeve, and that the adhesive sticks well to the blade. If the blade is longer than the safety sleeve, you can either use pieces that you might have cut off other safety sleeves, or you can use old newspaper to wrap around the heel of the knife (the part of the blade that is closest to the handle), all secured with adhesive tape. Make sure the tip of the knife is secured against the closed part of the knife guard.