K&N

K&N Engineering was founded in 1969 in Riverside, California by Ken Johnson and Norm McDonald — the K and N in the brand name. The company built its reputation on washable, oiled cotton-gauze air filters for motorcycles and performance cars before expanding into oil filters, fuel filters, and intake systems. K&N is widely sold through major retailers including Amazon, AutoZone, O'Reilly Auto Parts, Walmart, and Advance Auto Parts. K&N oil filters are sold under the "HP" (High Performance) series designation and are designed as direct replacements for OEM oil filters. The HP series features an integrated 1-inch welded hex nut ("Wrench-Off") for easier removal, a heavy-gauge steel canister, silicone anti-drain-back valve, and a synthetic-blend filter media. K&N is headquartered in Chatsworth, California and has been manufacturing filtration products in the United States since its founding.