Gabions are cages which are engineered from double twisted hexagonal woven steel wire mesh. Delivered flat-packed, gabions are assembled and then filled with stones at the project site. There are numerous uses for these modular units and are typically used to form flexible, permeable and monolithic structures such as retaining walls, channel linings, hydraulic control structures and erosion protection. They are increasingly being used in architectural applications as well. Gabion baskets are made from high quality steel wire, which is heavily galvanised to provide long term corrosion protection. An additional protective polymeric coating is also applied for gabions that are to be used in more aggressive environments, or where a longer design life is required.