Here are some characteristics of masks:

1. Disguise: Masks conceal one's identity or appearance.
2. Protection: Some masks provide protection from harm, like gas masks or surgical masks.
3. Expression: Masks can exaggerate or change one's facial expressions, like theatrical masks.
4. Cultural significance: Masks hold cultural or spiritual meaning in many societies, like Native American or African masks.
5. Artistic: Masks can be decorative and aesthetically pleasing, like Venetian or Carnival masks.
6. Functional: Some masks serve a practical purpose, like oxygen masks or diving masks.
7. Symbolic: Masks can represent characters, emotions, or ideas, like the masks of comedy and tragedy.
8. Transformative: Masks can alter one's appearance or persona, like Halloween masks or cosplay masks.

These characteristics highlight the diverse purposes and meanings of masks across various contexts.