Folding knives have a folding blade and their main advantage is compact size. Folding knives are also called pocket knives. Some folding knives may have a sheath for carrying a knife on a belt, others have a clip. The folding pocket knife can have a handle made of a variety of materials - wood, titanium, G10, micarta, carbon fiber, aluminum, antler, or horn. An important feature of the folding knife is the lock, which ensures the safe use of the knife and reduces the risk of injury. The most common lock types are liner lock, frame lock, back lock, or slipjoint. Maintenance of the folding knife is important for its proper function. The knife should be cleaned after use and the opening mechanism should be lubricated from time to time.