Universal air filter details
K&N Filters Universal Clamp-On Air Filter 4.5in Flange Oval (KNNRU-1021)
The K&N Filters Universal Clamp-On Air Filter 4.5in Flange Oval (KNNRU-1021) is designed for performance and convenience in custom and universal applications. Its centered flange and oval tapered shape offer a reliable fit while maximizing airflow. This clamp-on filter is made with washable, reusable cotton gauze material, which helps maintain engine efficiency and power. It is ideal for many setups and supports long-term performance without frequent replacements.
Features and Specifications:
Flange Type: Centered
Filter Shape: Oval Tapered
Flange Inside Diameter: 4.5 in (114 mm)
Base Outside Length: 5.875 in (149 mm)
Base Outside Width: 3.25 in (83 mm)
Flange Length: 0.625 in (16 mm)
Height: 8 in (203 mm)
Top Outside Length: 4.5 in (114 mm)
Top Outside Width: 4.5 in (114 mm)
Engineered Power: Advanced air filter media enhances horsepower, acceleration, and overall engine performance.
Superior Protection: Four layers of premium cotton gauze with a specialized tacking agent trap harmful contaminants effectively.
Durable Construction: Built with high-quality materials and precision manufacturing for long-lasting performance.
Long Service Life: Under normal highway conditions, it requires cleaning only every 75,000 miles, equivalent to about five years.
Easy Installation: Pre-oiled and ready to use, making it a simple and cost-effective upgrade for better performance.
Versatile Fitment: Designed for compatibility with a wide range of applications.
Eco-Friendly: Reusable design helps reduce landfill waste from disposable filters.
Product identification
- Brand: K&N Filters
- Model / MPN: KNNRU-1021




