Abstract: A mating closure and finish system particularly adapted for use with containers, e.g. bottles containing carbonated beverages which generate gas in the bottle headspace and where the bottle finish incorporates at least two equally spaced helical cam tracks. The closure is comprised of plural sets of cam followers which fit into the cam tracks and where the cooperation between the cam tracks and cam followers produces an axial movement of the closure as it is rotated on the finish. For a two track system, which is the preferred embodiment, each track starts 180.degree. from each other and makes at least one full turn around the circumference of the finish. Also included are intervening stops and tapered speed bumps that contact and impede the cam follower(s) in the cam tracks during closure removal to effect a delay. Raised thread segments which define the cam tracks are intersected by a plurality of vertical venting slots or pathways along their helical length to vent headspace gas.