Product:
These are likely sealing rings or gaskets, potentially made of silicone or PTFE, used in various applications to prevent leaks.

Applications:
They can be used in plumbing, automotive, or industrial settings, including for sealing pipes, valves, or other components.

Variations:
These rings come in various sizes and materials, so it's important to select the correct type for your specific needs, considering factors like temperature resistance and chemical compatibility.