For the performance and long life of your equipment, clean air is essential because a small amount of dust that can result in expensive damage. AUSFIL air intake filters principally use felted polyester, however in a reciprocating type compressor which is prone to “oil blow back”, AUSFIL 5 ply media is used. AUSFIL 5ply media is un-affected by oil and permits full airflow as well as exhibits excellent life. In the case of breather types, two way media is used. Air cartridges best suit for engines, compressors, blowers, vacuum and breathers.