It's nice to be light and compact, but it's too small. When covering the nose tightly, the lower lip is so tight, it is hard to talk and the patch is easy to slip and it is hard to dry. It is impossible for people who want to wash them everyday and want to use it, or attach importance to fit. In addition, it is easy to get dirty and hard to fall off, the cover of the filter tends to come off. For simple use.