A dive knife is a specialized tool designed for underwater use, primarily by divers and snorkelers. It typically features a corrosion-resistant blade made from materials like stainless steel or titanium, ensuring durability in saltwater environments. The knife often has a blunt tip to prevent accidental punctures and may include serrated edges for cutting through tough materials like rope or fishing line. These knives are usually attached to a diver's gear, such as a buoyancy control device or leg strap, for easy access. Dive knives can also serve safety purposes, allowing divers to free themselves from entanglements or assist others in emergencies.