The K&N RG-1001RD-L is a red cotton gauze, round tapered universal clamp-on air filter with a chrome metal top, sold in multi-language packaging. The manufacturer describes it as a high-flow, washable, reusable filter, and its molded rubber flange is designed to absorb vibration and clamp securely onto the intake tube. It suits custom intake tubes, track builds, and off-the-shelf intake projects that need a filter sized to a specific inlet rather than a vehicle-specific box element.
The main reason to pay for this filter over a disposable paper element is reuse. The manufacturer says the filter typically needs cleaning only about every 75,000 miles under normal highway driving, so one filter can outlast several replacement cycles. Three flange inserts let the same filter fit 4-inch, 3.5-inch, or 3-inch inlet tubes, and the rubber flange can stretch up to 1/16 inch to cover in-between diameters. Because the filter ships pre-oiled, it is ready to clamp on the moment it comes out of the box. Confirm the flange diameter, 1.125-inch flange length, and 5.5-inch overall height against your inlet and surrounding clearance before ordering. Keywords: 4 inch universal cone air filter, clamp-on cotton gauze intake filter, round tapered high flow air filter, K&N RG-1001RD-L, reusable performance intake filter.
The manufacturer states it includes inserts to fit three different flange diameters: 4 inch, 3.5 inch, and 3 inch.
The manufacturer suggests cleaning about every 75,000 miles under normal highway driving. The filter's re-oiling amount is 1.61 oz (48 ml). Follow the manufacturer's cleaning guidance for the procedure.
No. The manufacturer states the filter is pre-oiled and ready for use. Re-oil only after it has been cleaned.
This is a clamp-on, low-difficulty swap that typically needs only basic hand tools and a few minutes. Loosen the existing intake clamp, pick the flange insert that closely matches your inlet, seat the rubber flange fully over the tube, and tighten the clamp. Before driving, check that the filter top clears hoses, wiring, and heat shields, and look for air leaks at the connection. Because the filter is universal, the most common mistake is a poor flange fit, so test-fit the insert and flange before final tightening.
