Our XS Series of Professional Grade Bowden Tubing is made from the highest quality PTFE. Our secret blend of high lubricity additives turns it a deep blue color.In 2016 we developed the XS formula of high lubricity additives combined with smaller inner diameter, 1.9mm +/- 0.05mm, in order to print flexible filaments with Bowden driven printers. Beta testers quickly discovered that it allowed them to lower retraction as well, which has proven to be an even bigger selling point.High Lubricity Additives make our XS Series tubing the lowest friction Bowden tubing on the market. Less friction means more responsiveness, less retraction, more accurate prints, less slippage, wear, and tear on the extruder, and less clogging when printing chunky filaments such as some woodfills or ironfills.Lower retraction means time saved every time the extruder retracts. Over the course of a print, a few milliseconds here and a few there add up to a lot of time saved.1.9mm +/- 0.05mm Inner Diameter Reduces the "wiggle room," or buckling, inside the tube, allowing you to print flexible filaments even on the longest Bowden systems. Most of our printer farm printers are RostockMaxV3s and Tevo Little Monsters.High Temperature Resistance due to using only the highest quality PTFE. Our XS tubing will operate at even higher temperatures than our TL.