a plastic bottle has a champagne base that includes a planar standing ring located between a lower margin of a convex heel of the base and a lowermost portion of a central concavity within the standing ring . by making the inside vertical radius of the convex heel lower margin and central concavity lowermost portion sufficiently small , the bottle is shown to exhibit increased top load strength without any increase in plastic . the bottle also has a larger standing ring diameter leading to a more stable bottle .