Razor wire has many circles. Tie every two adjacent circles by clips, and a spiral razor wire is created. The clips one circle needed is depended on the diameter of the circle. Generally speaking, the diameter of an opening circle would be 5-10% less than its original size. Circles of spiral razor wire cross each other, leaving no space for a person or middle-sized animals. Spiral razor wire improves security level. Hence, it is widely used in boundary, residential and commercial places, prison and institutions.