High security chain tried and tested in the streets of new york10 mm six sided hexagonal chain links made from triple heat treated boron manganese steel for ultimate strength including a larger cinch ringnarrow inner width of individual links prevent leverage attacksev 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 force14 mm ovalised hardened steel shacklesliding d