Gabion mattress can be made of hexagonal double- twisted mild steel wire mesh. Mattresses can be supplied in various length, widths and height. The tolerances of mattress' dimensions are ±3% in length, ±3% in width and ±2.5cm n height. In order to strengthen the mattresses, all the edges of the mattress are selvedged with a wire of greater diameter. Gabion mattress has a hexagonal mesh with the opening of 80x100mm with 2.5mm mesh wire and 3.0mm selvedge wire diameter. All gabions and mattresses are supplied with the baskets and are used to lace together the mesh panels during the erection process. Mattresses and gabion baskets are also available with a 0.5mm thickness P.V.C. coating to enhance the resistance of the baskets to corrosion. This provides an overall increase in diameter of 1mm to all wires used in the manufacturing process. The river mattress is a structure made of hexagonal double twisted wire mesh. River mattresses are filled with stones at the project site to form flexible and permeable, monolithic structures such as river bank protection and channel linings for erosion control. Surface treatment of gabion mattress: The woven steel wire used to manufacture the mattress is heavily zinc-coated soft temper steel.