Concertina wire is formed in large coils which can be stretched like a concertina. Rigid and sharp blade frightens or hurt any person or animal that want to go through concertina wire fence. Concertina razor wire is available in galvanized, PVC coated and stainless steel wire materials. Broadly speaking, galvanized razor wire is very effective and relatively cheap. Concertina wire is supplied in single coils, double coils or crossed spiral coils. Besides coiled concertina wire, straight razor wire is also provided, which can be welded to fences.