The Thermaltake Pacific Compression Series provides a complete solution for enthusiast and custom PC builders to meet the needs of setting up a complete water cooling system. With G1/4" durable copper fittings, finished in chrome coatings, take every detail seriously. Choose from: 5/8" and 3/4" OD compression size options to make your system a showcase for all to see with high quality components from Thermaltake.Tt LCS Certified is a Thermaltake exclusive certification applied only to products that pass the design and hardcore enthusiasts standards that a true LCS chassis should hold to. The Tt LCS certification was created so that we at Thermaltake can indicate to all power users which chassis have been tested to be best compatible with extreme liquid cooling configurations, ensuring you get the best performance from the best features and fitment.High-flow and Leak-free Design Made in Taiwan, the fittings allow proper connection to G1/4" ports, securing properly to cooling components while providing an even seal around the tubing. The fittings are available in chrome and black finishes, include one preinstalled O-ring. Use flexible tubing for all your water cooling needs.For tubes:- Inner diameter: 1/2" (13 mm)- Outer diameter: 5/8" (16 mm)Remarkable Expansion Thermaltake offers a full line of Pacific Series components for enthusiasts to build up aesthetically-superior water cooling systems by incorporating externally-modular upgrades for their chassis.