Brads or pins are a fastening element designed to satisfy a compromise. On the one hand they must disappear as much as possible, on the other they must ensure a stable, firm, sturdy fastening. For this reason they are made with very small diameters, under one and a half millimetres, and the head is barely pronounced so as to be almost invisible. The finishes – galvanised, burnished or stainless – are mainly to prevent rust from forming.