New york chain 100cm with evo4 disc lock high security chain tried and tested in the streets of new york four sided trapezoidal chain links made from triple heat treated boron manganese steel for ultimate strength narrow inner width of individual links prevent leverage attacks ev series 4 disc lock has flat keyway locking mechanism for extensive holding power and high picking resistance and an ovalised extra strong crossbar to withstand pull force and cut force 14 mm hardened steel