The K&N RE-0850 is a round tapered universal clamp-on air filter with cotton gauze media, a 4-inch flange inside diameter, a 6-inch base, a 4-5/8-inch top, and a 6-inch overall height, per the manufacturer's listing. Its red element and rubber top make it a candidate for custom intake tubing and airbox conversions where a stock OEM element will not fit. The manufacturer's High-Flow Original line is built around reusable filtration rather than disposable paper.
The main purchase argument is reuse. The manufacturer describes this filter as washable, and after cleaning it needs only a light re-oiling at about 1.22 oz (36 ml) of K&N oil. Owners on user forums often choose it over generic universal filters when a 4-inch inlet pipe is the constraint, since a matching flange size avoids reducers and extra couplers. Buyers searching for a K&N universal 4 inch flange cotton gauze filter, a washable conical intake filter, or a 6 inch base 4-5/8 top air filter are typically looking for exactly this footprint.
Because this is a universal part rather than a vehicle-specific one, fitment depends on matching the 4-inch flange, 6-inch base, and 6-inch height to your intake tube and airbox clearance. Measure before ordering. Owners on user forums also report that K&N told them MAF sensor problems would only come from applying too much oil, so re-oil sparingly.
No. The manufacturer lists it as a universal filter, so confirm that your intake accepts a 4-inch flange and that the 6-inch base and 6-inch height clear your airbox before ordering.
The manufacturer lists a re-oiling amount of 1.22 oz (36 ml).
Owners on user forums report that K&N indicated MAF issues would arise only if too much oil was applied, so use oil sparingly.
This is a clamp-on installation that needs basic hand tools and a hose clamp sized to your inlet tube. Owners on user forums commonly fit it to a 4-inch intake pipe. Measure the inlet first, slide the filter over the tube, and seat the 1.75-inch flange fully before tightening the clamp evenly so the filter does not sit crooked. Clean and re-oil the element at the manufacturer's 1.22 oz amount, and avoid over-oiling, which is the most common mistake that owners on user forums describe.
