Special attention need to give to the shape of the weld joint. They are made and design concentrating energy to permit a very fast welding cycle and strong weld joint. Their shape and form are sized according to the application and material to be welded. There are two kind of weld joint (1)near field welding – is less than 6 mm from the area of contact with the Horn (2) near field welding more than 6 mm from the area of contact with the Horn.