A skeleton support has a concave shape configured to fit around a nose and mouth of a user. The support includes a skeletal structure that defines a plurality of connecting regions which form a first common connection interface. A cover includes a mounting mechanism with a plurality of fastening units which form a second common connection interface corresponding to the first common connection interface. Each fastening unit is configured to removably engage a corresponding connecting region of the skeleton support to hold the cover together with the skeleton support and form a mask. Different skeleton supports or covers with a different size, shape, color, pattern, flexibility, or material that also include the corresponding common connection interface can be swapped out to adjust the mask.