Ideal for e-punched and Concave shoes. In addition to all of the same great features of the regular Liberty nail Liberty Cu horseshoe nails include Copper (Cu) Shield Technology. This technology provides much more protection than traditional horseshoe nails. Hoof wall, white line and sole are stronger and healthier when Liberty Cu nails are used on a daily basis. The Copper(Cu) Shield Technology is unique to Kerckhaert and Liberty Cu horseshoe nails.