The invention provides in a first aspect a closure (10) for a passageway such as a bottleneck. The closure (10) has a concertina element (16). When the concertina element (16) is released, the closure (10) can be removed from the passageway. The concertina element (16) may have folds (18), including compressible folds, may be in the form of a spiral. In a further aspect, the invention provides a second aspect a closure (110), which has a processing (132). The processing (132) may include a computer chip (134), is adapted to receive or convey various types of data, such as characteristics of the contents of the container closed by the closure (10). The first and second aspects may be combined.