This re-usable air filter is made from a synthetic fabric and not cotton.
But that oil reduces air flow through the filter and it can become easily clogged. Replacement filter;Synthetic fabric;No oiling required;3-year limited warranty;California Residents: WARNING Rugged Ridge Synthetic Air Filter - 17752.03 Our dry panel design never needs oiling, which keeps your mass airflow sensor from being damaged by excess oil!.No oil = No fuss, no mess and improved performance! Cotton filters are made porous and must be oiled to trap dirt and debris.