A container, comprising: a main body portion configured to contain a liquid; a container opening which provides a point of exit for liquid contained in the main body portion; a neck portion between the container opening and the main body portion, the neck portion comprising a cross-sectional area that is smaller than a cross-sectional area of the main body portion; and a pressure equalizer having at least one air inlet and being positioned in the neck portion, characterized in that: the pressure equalizer comprises the neck portion a shoulder portion, and a first flange, wherein the pressure equalizer enables the liquid to exit the container opening and simultaneously enables air to enter the main body portion through the at least one air inlet such that the flow of the liquid from the main body portion is substantially continuous, smooth, and without glugging, wherein the container opening comprises a diameter of less than about 15 mm and wherein the main body portion comprises a second flange at its top during its manufacture, the second flange having an inner diameter and outer diameter, wherein the outer diameter of the first flange is larger than the outer diameter of the second flange, wherein the second flange is attached to the pressure equalizer, and wherein the entirety of the pressure equalizer is above said first flange. a main body portion configured to contain a liquid; a container opening which provides a point of exit for liquid contained in the main body portion; a neck portion between the container opening and the main body portion, the neck portion comprising a cross-sectional area that is smaller than a cross-sectional area of the main body portion; and a pressure equalizer having at least one air inlet and being positioned in the neck portion, characterized in that: the pressure equalizer comprises the neck portion a shoulder portion, and a first flange, wherein the pressure equalizer enables the liquid to exit the container opening and simultaneously enables air to enter the main body portion through the at least one air inlet such that the flow of the liquid from the main body portion is substantially continuous, smooth, and without glugging, wherein the container opening comprises a diameter of less than about 15 mm and wherein the main body portion comprises a second flange at its top during its manufacture, the second flange having an inner diameter and outer diameter, wherein the outer diameter of the first flange is larger than the outer diameter of the second flange, wherein the second flange is attached to the pressure equalizer, and wherein the entirety of the pressure equalizer is above said first flange. the pressure equalizer comprises the neck portion a shoulder portion, and a first flange, wherein the pressure equalizer enables the liquid to exit the container opening and simultaneously enables air to enter the main body portion through the at least one air inlet such that the flow of the liquid from the main body portion is substantially continuous, smooth, and without glugging, wherein the container opening comprises a diameter of less than about 15 mm and wherein the main body portion comprises a second flange at its top during its manufacture, the second flange having an inner diameter and outer diameter, wherein the outer diameter of the first flange is larger than the outer diameter of the second flange, wherein the second flange is attached to the pressure equalizer, and wherein the entirety of the pressure equalizer is above said first flange.