The long Links and long links are part of our Fursaver range, it is still used as a check chain collar in the normal manner, however the long & shaped links mean it is less likely to catch in the dog's coat making it a very popular choice for the long haired dog. The 4mm check, not "chockâ€, chains are the one of our medium, slightly heavier sizes available. While the 4mm chains are the one of our heavier sizes available. Suitable for both medium and large dog breeds these chains are often used for dog training and by the everyday dog owner. About the finish: U2219 Chrome Plated chains undergo first nickel, and then chromium plating to produce that strong metal shine. These chains are strong and durable, however are not recommended for dogs that spend a lot of time in and around water, especially saltwater, or dogs that have skin sensitivity. All Herm Sprenger Stainless Steel chains are marked with a metal label and a shiny red point with HS-GERMANY in the middle, along with "HS-GERMANY INOX†stamped on the rings. Important note: For those who have not used Check, not "chockâ€, Chains before, it is always recommended to contact and seek assistance from your local dog trainer before using this training tool with your dog.