4-layer filtration,
1st layer: 20gsm PP non woven isolation layer
2rd layer: 25gsm filter paper, BFE>95 &99%.  
3th layer: 20gsm PP non wove 
4th layer: Skin friendly non-woven fabric layer

Advantage:
Filters bacteria and dust 95%.
Easy to carry flat fold design.
Hygienic & Skin friendly.
Disposable material environment friendly use and throw.