There is a separate category of rivets, which is called exhaust. With such fasteners, you can join even more than two fastened parts. The design of such rivets consists of two elements: a thin rogue that has a small ball at the end and tube. They have a different length, and can be corrugated, petal and others. Also, such rivets are distinguished by the configuration of their side, which may have a standard shape, secret or increased.