"Designed for 16mm OD PETG tube 4 x O-rings leak-free design Patented design to build up easily Compatible with G¼” Thread Special anodizing surface treatment compatible with PETG, Acrylicand Cooper tubing Dimension D26 x 21 (H) (mm) Weight 320 g Material CU Note PETG Tube to G1/4 Applicable OD : 16 mm Screw Thread G 1/4"