The Black Ops® HEPA Foam Pre-Filters are designed to remove pests, dust and pollutants from your indoor gardening space. Instead of using a synthetic oil to lubricate the surface of the filters, the Black Ops® HEPA filters use an oil that is derived from a plants natural fatty acid. Our oil and cleaner is 100% biodegradable. These pre-filters offer excellent filtration and with proper cleaning will last a long time. Each filter comes pre-lubricated in a sealed bag.