P3 Particulate filter for solid and liquid hazardous and radioactive particles, micro organisms. A wide range of filters and cartridges are available to cover most applications.Filters are common to 7000 and 9000 series but DO NOT FIT 8000 Series masks. Filters may be combined without the need for any adapters.For example you can add any particulate filter to any gas cartridge or use the gas or particulate filter alone.