Titan® Chain Dog Prong Training Collar with One-Handed Quick Release Snap is argon welded and chrome plated for maximum strength and durability. There is no need to fasten or unfasten links to remove the training collar from your dog. Extra links and vinyl comfort tips are available for this training collar. Available in Fine 2.0 mm x 14". medium 3.0 mm x 18", heavy 3.3 mm x 20" and x-heavy 4.0 mm x 22". Prong Chain training collars are safe, effective training tools with proper use. They are not to be used for tie out.