A container system for liquids includes a container body with a mouth, a resilient stopper and a cap. The stopper has a body portion closely received within the mouth, and an annular flange projecting radially outward from the body. A resilient annular spring element is located between the flange of the stopper and the cap, and biases the flange against the mouth of the container when the container is assembled and maintains a seal between the flange and cap. In one embodiment, the spring element has a unitary, tear-drop shaped geometry in cross-section with a rounded bulbous body portion smoothly tapering to a curved, radially-inwardly projecting lip, although the spring element could have other asymmetrical configurations such as a cone, helical, V, S or C shape in cross-section. The spring element defines at least two separate points of contact between the flange of the stopper and cap.

A container system for liquids includes a container body with a mouth, a resilient stopper and a cap. The stopper has a body portion closely received within the mouth, and an annular flange projecting radially outward from the body. A resilient annular spring element is located between the flange of the stopper and the cap, and biases the flange against the mouth of the container when the container is assembled and maintains a seal between the flange and cap. In one embodiment, the spring element has a unitary, tear-drop shaped geometry in cross-section with a rounded bulbous body portion smoothly tapering to a curved, radially-inwardly projecting lip, although the spring element could have other asymmetrical configurations such as a cone, helical, V, S or C shape in cross-section. The spring element defines at least two separate points of contact between the flange of the stopper and cap.

A container system for liquids includes a container body with a mouth, a resilient stopper and a cap. The stopper has a body portion closely received within the mouth, and an annular flange projecting radially outward from the body. A resilient annular spring element is located between the flange of the stopper and the cap, and biases the flange against the mouth of the container when the container is assembled and maintains a seal between the flange and cap. In one embodiment, the spring element has a unitary, tear-drop shaped geometry in cross-section with a rounded bulbous body portion smoothly tapering to a curved, radially-inwardly projecting lip, although the spring element could have other asymmetrical configurations such as a cone, helical, V, S or C shape in cross-section. The spring element defines at least two separate points of contact between the flange of the stopper and cap.

A container system for liquids includes a container body with a mouth, a resilient stopper and a cap. The stopper has a body portion closely received within the mouth, and an annular flange projecting radially outward from the body. A resilient annular spring element is located between the flange of the stopper and the cap, and biases the flange against the mouth of the container when the container is assembled and maintains a seal between the flange and cap. In one embodiment, the spring element has a unitary, tear-drop shaped geometry in cross-section with a rounded bulbous body portion smoothly tapering to a curved, radially-inwardly projecting lip, although the spring element could have other asymmetrical configurations such as a cone, helical, V, S or C shape in cross-section. The spring element defines at least two separate points of contact between the flange of the stopper and cap.