The most common hard tubes for liquid cooling are acrylic (plexiglass) or PETG (polyethylene terephthalate). They are cheap, easy to come by, and can be shaped and bent in every household. Size is often a water cooler's biggest concern, however the size of your tubing really doesn't impact your loop's performance at the end of the day. All tubing is measured with an O.D., or outer diameter, and an I.D., or inner diameter.Harder (or rigid) tubing like glass, acrylic, carbon and the more popular PETG offer the possibility to create some stellar-looking systems. Unlike softer tubing, these choices are not flexible, which is where a major headache lies.Acrylic is more scratch resistant, has a shiny finish and also clearer than PETG. But it can be broken if enough force is applied. PETG is 5 to 7 times stronger than acrylic and resists better to impact damage and drops. A more flexible material allows it to take more bending without breaking. That's why Dracaena used PETG for our hard tubing. Perfect quality in the best conditions and price will help you to build up your Computer water cooling system.