‘U’ Staple / Fencing Nails As the name suggests these are nails used mainly for fencing purposes in which chain links are mounted on angles or a net is to be covered on an angle frame or barbed wire on a cement pole. So these nails are used to fasten the wire or chain to the angle or pole. The main size available or used extensively is 40 mm (Length) x 10 g (Thickness) though other sizes available are 20 x 4, 25 x 12 and 30 x 10. They are ‘U’ shaped having a point on one end of the U and are galvanized finish and available in packing of 2.5 kg.