(57) A cap (4) comprises a circular wall (6), a cylindrical side wall (8), and a tamper evident ring (10) secured to the wall (8) by fracturable tabs. The interior of the wall is threaded (12), which in the preferred embodiment is three-start. Uniformly spaced around the ring (10) are three location formations (14), so arranged that the distance X between each pair of formations as measured between outer tangents thereto is approximately the same as, or slightly smaller than, the diameter Y in the corresponding part of the cylindrical wall from which the formations (10) extend. The caps may be fed in serial array, and by utilising a guide means which is engaged by the location means, each cap may be fed in turn over the neck of a filled bottle with the cap and neck in axial alignment, and with the threads of the cap in a known, desired relationship with the threads of the neck, and by pressure alone the cap may be fitted onto the neck so as to be of in sealing engagement therewith.