Below is a list of Rubber Tube manufacturers from California. A rubber tube is made from natural latex or synthetic rubber and is used in flow lines to transport liquids or gases. Natural rubber tubing is derived from natural latex, which is a product of several plant species, most notably the Pará rubber tree. Synthetic rubber is made from various molecules derived from petroleum. The inner diameter, outer diameter and thickness of rubber tubing can range in size from a few thousandths of an inch to several inches.