Your search for "p1 filter" revealed the following:

Odor Remover: The Smartmi 3-Stage Filter w/ OdourStop is designed to absorb various odors in the air, suitable for environments with pets, cooking odors, smoke, or smog. Stage 1: Preliminary Filter For Large Particles, removes the most common large particles...

Pollen Remover: The Smartmi 3-Stage Filter w/ OdourStop is designed to absorb hazardous elements like pollen, dust, and tiny pollutants, suitable for people who want to get rid of unpleasant airborne particles. Stage 1: A preliminary Filter For Large Particles...