Dry Air Filter Most new dwsign are now dry filter instead of oil filter. Our filter do not require old, it is reusable and washable. You can wash it with soap and water, rinse it until it is all dry up and use it again. We recommend you to check every 5000 miles to see if it needs to be washed. Hight quality Air filter will help to draw more clean air into your engine without dust and rocks to prevent any damages to the engine. Performance increases when engine absorbs cold air by passing though aluminum pipe to extract the heat to improves throttle response more horsepower.