First in a new generation of direct injection moulded closures for gable-top cartons Convenience is key in consumers’ choice between carton packages. They accept nothing less today than packages that are safe, easy to use, and with an inherent attractiveness that brings a smile to both consumers and producers. The latest Tetra Pak offering to meet this demand is the Delta Opening System: a new generation of integrated direct injection moulded openings on Tetra Rex gable-top cartons, for chilled liquid foods.