Simply to extend a 13 mm pipe or to connect two pipes with the same diameter. This junction is equipped with the Classic connection system. If this junction interests you, note that you will be entitled to a batch of three junctions adapted to 13 mm pipes. They are quite light, which makes them easy to use. On the other hand, they are very robust and resistant. From then on, you can use them for about two years. But still it is necessary to maintain them like all the other parts of your watering system elsewhere.