Quantity - 10 filters 
 
BFE99 filters certified to filtrate >= 0.1 micron particles, bacteria, pollen, dust, and other PM2.5 particles with 99% efficiency according to ASTM (American Society to Testing and Materials) Standards
 
Improvements:
Shape: Disk shaped filters that cover the full chamber as opposed to donut shaped
Durability: Last longer 
Wear and tear: Do not get damaged easily
 
Recommended Use Time: 4-6 days per filter depending on place and time of use -  (Replace if it is visibly soiled or torn).