Cartridge is interchangeable to the 5400 Series, 5500 Series, 7600 Series and 7700 Series respirators. Color coded for quick and easy identification. Eliminates the need to inventory several different kinds of cartridges and filters. P100 prefilters are 99.97% minimum filter efficiency in removing particulates and oil proof. They may be used without restrictions in atmospheres that contain oil based aerosols