Abstract: A sleeve-like component 1 is adapted to welded to a plastic bag containing a liquid to be dispensed such as wine or beer. The sleeve has an outer tubular part and an inner tubular part defining an annular space adapted to receive one end of a tube mounted on a tap assembly. The tube on the tap assembly has a peripheral rib which engages a recess formed on the outer tube part of the sleeve thus ensuring that a very good seal is provided and also helping to ensure that the tap will not be separated from the sleeve even if subjected to high pressure from the liquid within the bag which may be a carbonated beverage or a fermenting liquid.