Dull? Even the highest quality utility knife with the best blade will eventually become dull. Of course, this always happens at the most inconvenient moment. Before getting frustrated, having a replacement blade on hand is ideal. In most cases, you can simply swap it out, and you'll be able to cut, separate, or open anything without worry again. If you have a Secumax 350 from Martor, you'll find the corresponding replacement blades here. The blades can be easily replaced without any tools. Additionally, a replacement blade can be stored in the handle of the knife. This way, if a blade becomes defective, you don't have to return to the storage room right away, which would take a lot of time; instead, you can quickly replace the blade and then swap the replacement blade in the handle during your next visit to the storage room.