Razor wire is a type of fencing usually used in security applications, or to prevent extremely stubborn livestock from escaping. It is similar to barbed wire in construction, but features sharp razor like shapes cut from steel tape, rather than barbs. Although the words “razor wire” conjure up an image of fencing festooned with razors, the name is actually taken from an early brand name, “Razor Ribbon,” which was used to distinguish the fencing from barbed wire.

Manufacture of razor wire began in the First World War, when several German companies realized that cutting steel tape with dies was cheaper and more efficient than making barbed wire. This early product was called razor tape, and was actually weaker and easier to pass through than barbed wire, as a set of shears could quickly cut through it. In the 1980s, razor wire with a reinforced core of steel wire began to be offered. This type of razor wire is made by crimping razor tape onto the wire core.

While razor wire comes in large coils designed to be installed in strung lines, it is more commonly seen in the form of concertina wire. Concertina wire is wire which stays coiled, making it more difficult to pass over or through. The coils range in size, and are designed to pack down flat, making concertina wire ideal for military applications. When a length of wire is needed, it can be quickly pulled out, and the coils can be left tight or more loosely arranged, depending on how much of a deterrent needs to be created.

Typically, razor wire is used to top security fences. An unprepared individual attempting to get into or out of a secured area will have difficulty getting around razor wire, especially if the concertina configuration is used. Commonly, security fences are also curved, to make climbing even more difficult, and determined security companies may also electrify the wire. It is also used on livestock fences, as some livestock will crash through barbed wire fencing, but not razor wire.