Closure system and kit

A closure system for closing an opening of a container, comprising:

• a stopper member made of an elastic material and having a plug portion configured to tightly fit into the opening of the container and a cover portion configured to abut a boundary surface adjacent to the opening of the container;
• and
• a cage member made of a shape-retentive material, wherein the cage member has a stopper contacting section, a clipping structure and an intermediate section between the stopper contacting section and the clipping structure,
• wherein the clipping structure of the cage member is configured to clip in a corresponding structure of the container,
• wherein the cage member is configured such that the stopper contacting section of the cage member applies a pressure to the cover portion of the stopper member to push the cover portion of the stopper member onto the boundary surface of the opening of the container, when the plug portion of the stopper member is fitted into the opening of the container and the clipping structure of the cage member clips in the corresponding structure of the container,
• wherein the cover portion of the stopper member has a circumferential cage notch directed away from the boundary surface of the opening when the plug portion of the stopper member is fitted into the opening of the container, such that the cage notch of the cover portion of the stopper member collapses in dependence of a force applied on the stopper member when the stopper contact section of the cage member pushes the cover portion of the stopper member,
• wherein the cover portion of the stopper member has a circumferential container notch directed towards the boundary surface of the opening when the plug portion of the stopper member is fitted into the opening of the container, such that the cage notch of the cover portion of the stopper member collapses in dependence of a force applied on the stopper member when the stopper contact section of the cage member pushes the cover portion of the stopper member, and
• wherein the circumferential cage notch of the cover portion of the stopper member is radially offset relative to the circumferential container notch of the cover portion of the stopper member, and
• wherein the circumferential cage notch is disposed at a first radial position on the cover portion of the stopper member and the circumferential container notch is disposed at a second radial position on the cover portion at the stopper member, and wherein the circumferential cage notch is the only notch of the cover portion at the first radial position and the circumferential container notch is the only notch of the cover portion at the second radial position.