The Eiszapfen PRO hard tube fittings from Alphacool are the next step in development for the familiar Eiszapfen fittings. In the development of the fittings Alphacool concentrated on a specific problem. deforming PETG hard tubes at high temperatures. PETG can start to deform at 60°C. Although such a temperature is usually rarely reached. it can still occur. The Eiszapfen PRO fittings prevent this problem from the outset and hold the tubes in position.The deformation is prevented by the new nylon inserts inside and stabilizes the hard tubes. Furthermore. the fitting still has an O-ring and a compression seal. However. the contact area is much larger than with normal O-rings. which provides a better grip. With the insert and the compression seal. the tube is strengthened from the inside and outside.Even under heavy loads the HardTube does not slip. Alphacool has tested the tensile strength of up to over 8kg. so there is no need to worry about loose tubing.