K&N High-Flow Universal Clamp-On Air Filter RC-4780 — 4" Flange, 9.5" Tapered, Washable High-Flow Performance

The K&N RC-4780 is a washable, reusable high-flow universal clamp-on air filter with a 4" flange and 9.5" tapered body designed to increase airflow and last the life of your vehicle.

This clamp-on filter from K&N pairs multilayer cotton-gauze media with a pliable molded rubber flange to deliver improved airflow, durable mounting, and repeatable filtration without frequent replacements. It’s built to fit diverse intake setups thanks to its universal tapered (cone) shape, 4-inch flange diameter, and rugged construction. Pre-oiled and made in the USA, the RC-4780 targets enthusiasts and professionals who want a dependable, serviceable air filter that lowers long-term costs and reduces disposable waste.

How does this filter affect engine breathing and performance?

The RC-4780 uses multiple cotton-gauze layers treated with a tackifier to allow higher airflow while trapping contaminants. Increased airflow can support better engine response and acceleration when installed and matched properly to your intake system. It won’t add forced induction or change engine tuning by itself, but it helps the engine access more air more cleanly compared to many stock paper elements.

• Six-layer cotton gauze media for balanced airflow and filtration
• Pre-oiled for consistent performance right out of the box
• Designed to improve horsepower and throttle response when paired with proper intake setups

What are the physical dimensions and fitment details I need to know?

The RC-4780 is a round, tapered (cone-style) universal clamp-on filter that fits most applications requiring a 4-inch flange. It measures 9.5 inches tall with a flange length of approximately 1.6875 inches, making it suitable for many custom and replacement installations. The pliable rubber flange absorbs vibration and helps create a secure seal when clamped to different intake tubes.

• Flange inner diameter: 4.00 inches (fits 4" intake tubes)
• Filter height: 9.5 inches; tapered, round shape
• Flange length: 1.6875 inches for flexible attachment and clamping

How do I maintain and service this washable, reusable air filter?

K&N filters are designed to be cleaned and re-oiled rather than replaced frequently. Under normal highway driving, the media typically only needs cleaning about every 75,000 miles, though dusty or off-road use will require earlier service. Cleaning is straightforward with K&N cleaning kits; follow instructions for washing, drying, and re-oiling to preserve filtration performance and longevity.

• Clean roughly every 75,000 miles under normal conditions
• Use K&N cleaning and oiling kit for best results
• Dry and re-oil per instructions to maintain filtration efficiency

What durability and warranty information should I expect?

The RC-4780 features robust materials: multi-layer cotton media and a molded rubber flange that resists vibration and cracking. K&N backs the product with a 1-year limited warranty and manufactures these filters in the USA to consistent quality standards. Choosing a reusable filter reduces landfill waste compared with disposable replacements.

• Made in USA with premium materials
• 1-year limited warranty for manufacturing defects
• Reusable design reduces disposable filter waste

Who is this for: The K&N RC-4780 is ideal for car, motorcycle, or light-truck owners who need a universal clamp-on cone filter with a 4" inlet and a taller 9.5" profile—drivers seeking a long-lasting, serviceable filtration option that can improve airflow and lower lifetime filter costs. It’s also a good fit for builders and tuners installing custom intake piping or replacing aftermarket elements where a durable, washable filter is preferred.