Razor wire

Barbed tape or  razor wire is a mesh of metal strips with sharp edges whose purpose is to prevent passage by humans. The term "razor wire", through long usage, has generally been used to describe barbed tape products. While razor wire is much sharper than the standard  barbed wire, it is not actually  razor sharp.

The multiple blades of a razor wire fence are designed to inflict serious cuts on anyone attempting to climb through and therefore have a strong psychologicaldeterrent effect. In many high-security applications, barbed tape supplanted barbed wire, which could be circumvented relatively quickly by humans with tools, while penetrating razor wire barriers without tools is very slow and difficult, giving security forces more time to respond