A dive knife is an important piece of equipment that functions as a safety device and tool. Although a knife could be used to fend off a predator, divers typically use dive knives for untangling themselves from fishing nets, seaweed, and other hazards. Small (2-3 inches) and medium (4-5 inches) are the most popular sizes for dive knives. Those sizes are highly practical and can safely be secured to a diver's body. In addition, dive knives with both smooth and serrated edges are ideal for their ability to be used in nearly any situation. Avoid dangerous circumstances and bring a handy dive knife on your next excursion!