It is claimed that knives are among the oldest tools that mankind have ever been used. History said that knives were first made from bone, wood and other perishable materials that may not be present in our times now. Among the oldest knives, what is present still now are those that are made from flint. It was mentioned that the sharpening of these knives were done by thrusting a rock or other hard surface on the flint. Later on, harder materials like copper, bronze, iron and steel took the place of the olden knives made of stone, bone and wood. Some of the modern knives nowadays may even have more complex materials like titanium, ceramic and carbon fiber. Even with the technological advances today, the shape of a knife has not changed much. It still requires a handle and its purpose is still to cut or pierce. The variations of the design would come through the length of the blade, and can be double or singled edged, serrated or smooth and folding or fixed. Proceed to read on cheap butterfly knives . Even the handles are practically the same too, with some variation by adding a protection for the knuckles or as used for breaking glass. In order to hide the blade inside, there is the switchblade of the knife which has a spring that is tensioned so that as the button is triggered, the blade would slide into place in a fast manner. Police and the military, and criminals, often are the ones using this type since the blade is easy and fast to deploy while maintaining safety when not being used. A butterfly knife is another kind of knife that also hides the blade in the handle. It has two separate handles that secure each other. If you grab either side, the blade can be concealed or revealed and placed back into place. Read on good butterfly knives . Depending on the handling ability of the user, this knife can be spun around in different manners while showing the blade and the knife. And there are the pocket knives that also employ folding blades that are protected by the handle. Safety is a priority in this type versus its ability to be opened quickly. This is ensured with a lock that keeps the blade securely open while being used so that there is no accidental closure of the blade that could consequently harm the user. This style is often introduced in the market as survival knifes, and examples of these are pliers, tweezers, scissors, magnifying glasses and other tools that are incorporated into the handle. View this https://www.youtube.com/watch?v=erWzrzP_SIc