Blind rivets, also known as pop rivets, are a type of fastener used to join two materials together that cannot be accessed from both sides. They are commonly used in the construction and manufacturing industries to join metal, plastic or composite materials. Blind rivets consist of a cylindrical body with a hollow core and a mandrel, which is a thin metal pin that fits inside the core. Pop rivets are easy to install, requiring only a simple tool like a rivet gun or pliers. The mandrel is inserted into the rivet gun, which pulls the mandrel through the body of the rivet and expands it, creating a strong and secure joint.