The K&N RC-5139DK is a black Drycharger, a pre-filter sleeve that fits over a K&N round tapered air filter. The K&N Drycharger is a silicone treated, polyester wrap that is made to cover K&N Air Filters. The manufacturer pre-treats the material with a hydrophobic process designed to prevent splashes of water or mud from saturating the filter. For drivers who run gravel roads, rain-soaked autocross, or heavy tire spray, that extra layer is the real reason to pay more than a bare filter costs. The manufacturer says DryCharger wraps extend the length of time between air filter cleaning. Keep in mind that water repellency is not waterproofing, so this is a buffer rather than a seal.
The wrap is a closed-top, round tapered design. The manufacturer lists a 9 in base inside diameter, a 6.625 in top inside diameter, and a 7.5 in height, so measure your filter before ordering. Enthusiasts searching for a K&N pre-filter sleeve, a RC-5139DK filter wrap, or a closed-top Drycharger for a K&N intake will want to confirm that the dimensions match their filter's base and height. Its silicone-treated polyester is also meant to stop small particles, with the manufacturer noting it stops dirt and dust particles as small as 0.005" (127 microns) before they reach the K&N air filter.
The manufacturer states that DryCharger wraps stop small dirt particles while adding little restriction to the airflow of the filter.
No. The manufacturer says the DryCharger is water repellent, not waterproof.
The manufacturer indicates the water repellent treatment typically lasts 1 to 2 years.
