Thermaltake Pacific DIY LCS Black G1/4 PETG 16mm (5/8") OD Tube 90 Degree Dual Compression Fitting Cooling - CL-W099-CA00BL-A High Flow Leak Free Design: The fittings allow proper connection to G1/4 ports, securing properly to cooling components while providing an even seal around the tubing Black Coating Brass Fitting G 1/4" Port For PETG Tubes: Outer Diameter 5/8" (16mm) 6 Pre-installed O-Ring: Prevent coolant from leaking