The K&N RU-4680 is a round-tapered, red cotton gauze clamp-on filter with a centered 4-inch flange, a 6-inch base, and a 7-inch body. The manufacturer lists it as a High-Flow Original Universal Air Filter, and its four layers of cotton gauze, treated with a tacking agent, are meant to trap contaminants. The manufacturer also says the media is designed to add horsepower and acceleration, though actual gains depend on your engine and intake setup.
Compared with a disposable paper element or a cheap no-name clamp-on, the appeal is reuse. K&N filters are meant to be washed and reused rather than replaced on a schedule, and per the manufacturer's universal filter literature, the rubber flanges absorb vibration and can be stretched up to 1/16 inch to fit in-between sizes. The filter carries a 1 Year Limited warranty. For K&N RU-4680 buyers hunting a 4 inch inlet washable air filter, this is a practical long-term upgrade.
Because this is a universal part, the manufacturer's page does not list a vehicle-specific application, so confirm the 4-inch inlet and 6-inch base against your intake before ordering. The manufacturer's universal line is aimed at racing vehicles, generators, snowmobiles, tractors, and other equipment. The filter is pre-oiled and ready for use. Search terms this filter answers include round tapered cotton gauze air filter, universal clamp-on intake filter, and washable performance air filter 4 inch flange.
No. The manufacturer lists it as a universal clamp-on filter rather than a vehicle-specific part, so fit depends on matching the 4-inch flange and 6-inch base to your intake.
Yes. The manufacturer lists the filter as washable. Confirm the recommended cleaning interval with the manufacturer before setting a maintenance schedule.
Yes. Per the manufacturer's universal filter literature, the filter is pre-oiled and ready for use.
Installation is a clamp-on swap rather than a modification. Per the manufacturer's clamp-on instructions, loosen the hose clamp and remove the old filter, then install the K&N filter using the supplied hose clamp and tighten it fully. Wipe out any dirt in the housing before seating the new element, and make sure the flange seals so unfiltered air cannot bypass it. The manufacturer's high-flow intake sheets also recommend checking the system periodically for realignment, clearance, and tightening of all connections. Tool requirements for this exact part were not confirmed in my research, so check your intake before starting.
