Dolosse are normally made from un-reinforced concrete, poured into a steel mould. The concrete will sometimes be mixed with small steel fibers, to strengthen it in the absence of reinforcing. Construction is done as close as possible to the area of application as a result of their great weight. They are used to protect harbour walls, breakwaters, and shore earthworks. They are also used to bind sea-sand to prevent erosion. In the order of 10 000 dolosse are required for a kilometre of coastline.