Nails are hard metal sharp, common in wedge form of waja iron (a hard iron type) used to attach two materials by penetrating both. Spikes for special features can also be made from the sides, copper or aluminum.
The nails are actually blown on the material by using a nail gun that is moved by compressed air or a small explosive impulse. The attachment by the nail occurs with the frictional force in the upright direction and the power in the direction of the run. The end of the nail is sometimes bent to prevent the spikes coming out.
