How I use these:

The 5N11 Respirator Filter Cotton is designed to be paired with the 6001 Filter Cartridge and attached to the outside with a particulate filter cap. This product can be found in my product list, and is effective at capturing large particulate matter to extend the lifespan of your 6001 Cartridges, which can be quite costly. 

Replace the 5N11 when airflow restriction is noticeable while using your mask.

Description:

50PCS 5N11 Respirator Filter Cotton and 6001 Filter Cartridges are  effective at removing nonoily particles from the air, lasting up to 8 hours.

They must be used with a 6200, 6502, 6800, 7502, or FF402 respirator and cannot be used alone.

This package contains 50 pieces of high-quality electrostatic filter cotton that has a 95% filtering efficiency and low respiratory resistance.

Replace the filter cotton if it becomes damaged, dirty, or causes increased respiratory resistance.