Rubber, whether it's natural or synthetic, arrives at the manufacturing facility in large bales. Rubber bands are made by extruding the rubber into a long tube to provide its general shape. There are a number of different methods that can be applied at this point in the manufacturing process. Originally, and in some instances still today, the rubber tubes will then be placed on mandrels, curing the rubber with heat, and then slicing them across the width of the tube into little bands. This causes the tube to split into multiple sections, creating rubber bands. This is most commonly known as an "off-line" rubber extrusion process.