For high-level security needs, Super Barrier Concertina is the number one choice. The larger diameter coils (from 30" to 60") have adjacent loops clipped at multiple locations around the circumference (5 or more). This turns the concertina style coils into a dense maze of razor sharp deterrence. Super Barrier Concertina is the product specified most at medium to maximum security correctional facilities like the Federal Bureau of Prisons and most state correctional facilities. It is used throughout the military, surrounds the Guantanamo holding facility, secures numerous nuclear facilities, and is installed on the most violent sector of the San Diego border fence. It is installed on the top of fences and stacked in several rows as a ground barrier. It is also combined with other high security coils such as Rapid Barrier and Double Barrier to create a multi-faceted secure perimeter.