The K&N RC-3690DK is a black Drycharger pre-filter wrap for round tapered K&N air filters. The manufacturer describes it as a silicone-treated polyester sleeve with uniform micron-sized openings that allow high airflow while limiting how much water reaches the element. For a car that runs through puddles, mud, or dusty trails, a wrap like this protects a clean, oiled K&N element from splash and grit so it needs cleaning less often. The manufacturer says it adds little restriction, and it is sold as a wrap built for K&N's own filter sizes, which makes fit more predictable than a generic filter sock.
The manufacturer lists this Drycharger as the wrap for the K&N RC-3690 filter, with a 6-inch base diameter, a 4.5-inch top diameter, and a 9-inch height. Measure your filter before ordering, because sources disagree on whether it is a specific or universal fit. The wrap uses stitched elastic openings to hold it in place, and the manufacturer says the water-repellent treatment typically lasts 1 to 2 years. The manufacturer also states the wrap is water repellent, not waterproof. Track-day and off-road drivers searching for a K&N RC-3690DK Drycharger, a round tapered pre-filter wrap, or a water-repellent K&N filter sleeve will find this a practical way to extend filter service intervals.
The manufacturer lists it as the Drycharger wrap for the K&N RC-3690 filter, with a 6-inch base, 4.5-inch top, and 9-inch height. Confirm those dimensions against your filter before buying.
The manufacturer says the wrap adds minimal restriction to airflow. Owners on user forums have reported mixed impressions about airflow impact, so details vary and you should confirm with the manufacturer if this matters for your setup.
No. The manufacturer states the Drycharger is water repellent, not waterproof, and that the water-repellent treatment typically lasts 1 to 2 years depending on conditions and use.
The manufacturer says Drycharger wraps are meant to be run dry and can be cleaned with K&N air filter cleaner.
The wrap is a slip-on sleeve, so installation generally means removing the K&N filter from its housing, stretching the wrap's elastic opening over the filter, and reinstalling the assembly. The manufacturer describes the stitched elastic opening as what fastens the wrap, and no separate hardware is mentioned. Seat the elastic edges evenly so the wrap does not bunch or sit crooked on the filter's taper. When you service the filter, remove the wrap first and clean it separately so dirt does not get pushed into the element.
