Rubber Tubing made from natural latex, what is it? Natural latex rubber tubing has been given many names. Some people call it surgical tubing, exercise or fitness tubing, and dipped tubing as well as speargun bands and slingshot bands. Others may simply refer to it as “stretchy tubing”.,,Natural Latex Rubber Tubing made by Primeline's “Continuous Dip Process” creates a superior natural latex. The physical properties are better, the quality higher, and the colors more vibrant. In addition, Primeline’s tubing has only 50 micrograms or less of water extractable protein per gram. This is important since proteins in natural rubber can cause severe allergic reactions in those individuals who are allergic to the types of protein found in natural rubber. This is known as the “latex allergy”. No other rubber tubing can claim to have lower protein levels.,,Outer Diameter: 7/16",Inner Diameter: 3/8",,**Bulk Rubber Sold by the Inch.