The Gardena vent valve set protects your piping, sprinkler system, and original Gardena system from potential frost damage. The set consists of a standardized automatic air valve and three different attachments: the original Gardena system hose connector, the original Gardena system nipple, and the professional system nipple. To remove residual water from a piping system, use the hose connection attachment. First, screw the vent valve onto the attachment and then connect it to the outlet of the Pipeline Water Station. You will need either a standard bicycle pump or an air compressor. The compressed air blows the system clear of water, thus preventing frost damage. The drain valve set is a quality product made in Germany. Water, wherever it is needed. Easy access to water: pipelines underground.