With these compression fittings, Alphacool has created another masterpiece. These connectors promise both absolute impermeability and high quality. Fits all hard metal tubes with an outer diameter of 13mm. On the opposite side of the connector is the standard 1/4" thread. Available in deep black and chrome. First, the swivel nut is placed onto the tube, followed by a plastic plate which protects the O-ring and then the thick O-ring itself. Now the tube can easily be inserted into the attachment, where the second O-ring is tightly fitted to the tube. The final step is to slide the swivel nut onto the attachment and screw it into place. Due to its size, the swivel nut is not so easy to screw into place tightly. But even this was taken into account in the design, and so you can insert an 8mm hexagon wrench from underneath to hold the attachment tight. Technical Details: Material: chromatized brass Model: 17189