A one-piece plastic container comprising: an upper portion, a sidewall portion and a base portion, said sidewall portion is integrally formed with and extends from said upper portion to said base portion, said base portion closing off an end of the container; said sidewall portion defined in part by a plurality of horizontal ribs arranged substantially perpendicular to a longitudinal axis of the container, said horizontal ribs being movable to accommodate vacuum forces generated within the container and being movable to accommodate top load forces acting on the container, wherein said horizontal ribs are defined in part by an upper wall and a lower wall, said upper wall and said lower wall being separated by an inner curved wall, characterized in that said inner curved wall is defined in part by an innermost radius, said innermost radius measuring between approximately 0.0254 cm (0.01 inches) and approximately 0.0762 cm (0.03 inches), wherein said horizontal ribs each further include an upper outer radius and a lower outer radius, wherein both the upper outer radius and the lower outer radius each lie within the range of about 0.1778 cm (0.07 inches) to about 0.3556 cm (0.14 inches), and the sum of the upper outer radius and the lower outer radius being equal to or greater than about 0.3556 cm (0.14 inches) and less than about 0.712 cm (0.28 inches), wherein said horizontal ribs further include an upper inner radius and a lower inner radius,wherein the upper inner radius and the lower inner radius each lie within the range of about 0.2032 cm (0.08 inches) to about 0.2794 cm (0.11 inches), and the sum of the upper inner radius and the lower inner radius being equal to or greater than about 0.4064 cm (0.16 inches) and less than about 0.5588 cm (0.22 inches), wherein said horizontal ribs further define a horizontal rib width and a horizontal rib depth, wherein said rib depth is about 0.3048 cm (0.12 inches) and said rib width is about 0.5588 cm (0.22 inches) as measured from the upper extent of the upper outer radius and the lower extent of the lower outer radius, and the rib width to rib depth ratio is in the range of about 1.6 to about 2.0. an upper portion, a sidewall portion and a base portion, said sidewall portion is integrally formed with and extends from said upper portion to said base portion, said base portion closing off an end of the container; said sidewall portion defined in part by a plurality of horizontal ribs arranged substantially perpendicular to a longitudinal axis of the container, said horizontal ribs being movable to accommodate vacuum forces generated within the container and being movable to accommodate top load forces acting on the container, wherein said horizontal ribs are defined in part by an upper wall and a lower wall, said upper wall and said lower wall being separated by an inner curved wall, characterized in that said inner curved wall is defined in part by an innermost radius, said innermost radius measuring between approximately 0.0254 cm (0.01 inches) and approximately 0.0762 cm (0.03 inches), wherein said horizontal ribs each further include an upper outer radius and a lower outer radius, wherein both the upper outer radius and the lower outer radius each lie within the range of about 0.1778 cm (0.07 inches) to about 0.3556 cm (0.14 inches), and the sum of the upper outer radius and the lower outer radius being equal to or greater than about 0.3556 cm (0.14 inches) and less than about 0.712 cm (0.28 inches), wherein said horizontal ribs further include an upper inner radius and a lower inner radius,wherein the upper inner radius and the lower inner radius each lie within the range of about 0.2032 cm (0.08 inches) to about 0.2794 cm (0.11 inches), and the sum of the upper inner radius and the lower inner radius being equal to or greater than about 0.4064 cm (0.16 inches) and less than about 0.5588 cm (0.22 inches), wherein said horizontal ribs further define a horizontal rib width and a horizontal rib depth, wherein said rib depth is about 0.3048 cm (0.12 inches) and said rib width is about 0.5588 cm (0.22 inches) as measured from the upper extent of the upper outer radius and the lower extent of the lower outer radius, and the rib width to rib depth ratio is in the range of about 1.6 to about 2.0.