Anti-fatigue rubber tubing for cellists, violists, and violinists; for bow tubing for bass players, visit here. These tubes will fit the bows of violins, violas or cellos. They are all the same size tubing. Tubing is installed over the bow leather and slightly over the frog. Cushions the thumb contact area and provides added grip. Allows string players to relax the thumb and helps prevent pain at the thumb tip, cramping, and fatigue.Length Options: 2 inches (standard length for cellos) 3 inches (+$7.50) 4 inches (+$15.00 Color Options: Clear (latex-free). Black (contains latex). Amber (contains latex, slightly softer than black). Note: Although this material provides some cushion, this material is not squishy or spongy. Latex is the easiest to install and remove. The Latex-free goes on easy with lubrication, but is a bit tougher to remove.See video below for installation instructions.