round chain with short links looks appealing wire gauge 2.5 mm chain runs well through the ring to bring sharp correction ultra plate provides limited traction effect infinitely adjustable thanks to the ultra plate two O-rings with the Herm Sprenger quality stamp Black stainless steel - solid: increased rust resistance reduced abrasion because of the galvanizing process, so links won’t abrade even after years of use suitable for conditions of high humidity contains nickel, so will not do for nickel-reactive dogs suitable for dogs with dark fur only as it may stain light fur has extraordinary dark color and blends well with dark coated dogs wipe it down with a clean, damp cloth for more stubborn dirt, use a little water, some mild soap, and a soft-bristled toothbrush after cleaning, wipe it down with a clean, dry cloth